Finnish Economic Papers – Volume 22 – Number 1 – Spring 2009 Factor Supply Changes in Small Open Economies: Rybczynski Derivatives under Increasing Marginal Costs* ANDREAS PFINGSTEN University of Münster, Department of Banking, Universitätsstr. 14–16, D-48143 Münster, Germany; email: [email protected] and REINER WOLFF University of Fribourg, Department of Quantitative Economics, Boulevard de Pérolles 90, CH-1700 Fribourg, Switzerland; email: [email protected] We discuss the validity of Rybczynski’s theorem under increasing marginal costs within firms or industries. In particular, we show that an extra supply of any factor may lead to an expansion of all sector outputs if at least one sector permits input substitution. We provide a corresponding necessary and sufficient condition. This condition can even be satisfied when the equilibrium is Walrasian and Marshallian stable. Our findings are also robust with respect to aggregate improvements in total factor productivity which raise the economy’s outputs beyond private returns. (JEL: D50, F11) 1. Motivation The famous theorem by Rybczynski (1955) is one of the single most significant insights of modern pure trade theory. Given the standard Heckscher-Ohlin framework of a small open * Earlier versions of this paper have been presented at North American and European meetings of the Econometric Society, at meetings of the German and European Economic Associations, and at various faculty seminars, including the Universities of Essen, Göttingen, Linz, Munich, British Columbia/Vancouver, and Zürich (ETH). We are indebted to C. Blackorby, W. Buhr, W.E. Diewert, T. Hens, G. Gabisch, W. Kohler, and J. Mercenier, among others, for helpful comments. Two anonymous referees provided insightful suggestions which lead to a considerable improvement of the paper. economy with two commodities and factors, the theorem states that an extra supply of some input will induce the production sector where this input is used more intensively to expand more than proportionally. At the same time, the other sector will contract. Proofs of this theorem usually rely on the convenient simplification that scale effects can be assumed away due to constant returns in production. The underlying notion of a small economy is a relative concept. Under globalization, an economy or economic region may quickly become small relative to a growing world market. Not surprising, the theorem does not in general carry over to variations of the base para Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff digm. Blackorby/Schworm/Venables (1993, p. 426) have shown that under a regime of joint production deviations from the usual Rybczynski adjustments may even occur for constant returns to scale. Other authors, starting from a seminal paper by Jones (1968), have introduced technologies with scale economies or diseconomies. An important feature of these technologies is that any improvement or deterioration in the overall productivity of inputs is considered as an output externality which is not within the exploitation potential of a single firm or industry. From the perspective of any one firm, though, the constant-returns hypothesis is maintained. The concept of perfectly competitive markets can thus be preserved. So-called comparative-statics paradoxes may then emerge and may sometimes persist despite supplementary conditions. The literature also indicates that these paradoxes do not occur, however, when the commodity markets are Marshallian stable (cf. Mayer (1974), Panagariya (1980), Ide/ Takayama (1988, 1990), Ingene/Yu (1991), Ishikawa (1994), Burney (1996)). The assumed constancy of internal returns to production can be motivated on a-priori grounds by a standard replication argument: A firm may always choose to reiterate its activities – such that, e.g., a duplication of the firm’s inputs must result in twice as much output as before. Yet this popular view has been criticized by Buchanan/ Yoon (1999, pp. 517) as converting a production function into an ‘engineering tautology’. To quote Kemp (1969, p. 154): “The assumption of constant returns to scale [...] has been a very convenient assumption since it has enabled us to focus attention [...] It is conceivable, however, that Nature is blind to the comforts of academic economists.” In a more recent contribution, Choi (1999, p. 18), providing a number of further references, points out that the assumption of constant returns to scale “[...] precludes any divergence in industrial returns to scale, which have been recognized as an indisputable phenomenon since the early days of economic science.” 10 Empirical support against the constant-returns assumption has been provided by the new literature on the total factor productivity of a large number of (mostly manufacturing) industries in Europe (Caballero/Lyons (1990, 1991), Oulton (1996), Midelfart/Steen (1999), Lindström (2000), Henriksen/Midelfart/Steen (2001)) as well as in Canada and in the United States (Caballero/Lyons (1992), Benarroch (1997)). While the main focus of this literature is on positive inter-industry externalities, many authors also found strong evidence of decreasing returns to scale within firms or industries or within regions (e.g., Caballero/Lyons (1990, 1991), Burnside (1996), Lindström (2000)).1 We conclude that decreasing returns are a legitimate and even important topic to be analyzed in the context of the Rybczynski problem. Therefore, our model of a small open and competitive economy with two or more goods and factors imposes the conjugate assumption that firms operate under decreasing returns to scale, i.e. with increasing marginal costs. This economy can be interpreted as a geographic region which is exposed to global competition. We assume that the firms in this region benefit from agglomeration advantages and knowledge spillovers which they perceive as an exogenous productivity gain. The model is otherwise fairly standard. In particular, following Woodland (1982), our analysis is carried out entirely in dual space. We start from (minimum) cost functions and, hence, exploit the structure and regularity imposed by duality theory irrespective of the functional form of the underlying technology.2 In contrast to the conclusions of earlier writers and Rybczynski’s theorem notwithstanding, in our model all outputs may benefit simultaneously from larger endowments. As a notable exception in the literature, Ylönen (1987, pp. 214–216) already pointed out that such an outcome can arise – as a plausible implication – 1 The reader may consult Basu/Fernald (1995, 1997) for a critical literature assessment from a methodological perspective. 2 Thereby, we need no longer refer to traditional, however less convenient, concepts such as the ‘production possibility locus’ of an economy (cf. Herberg/Kemp (1969)). Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff from the Hansson/Lundahl (1983) model of a 2 × 2 economy with differentiable and homo geneous production functions, if the degrees of homogeneity are less than one for both goods. (Also cf. a respective brief remark by Hansson/ Lundahl (1983, p. 538).) We provide necessary and sufficient conditions for our general result which requires that at least one production sector permits input substitution. Our conditions are illustrated by a selection of examples. These examples cover both substitution and non-substitution technologies, as well as technologies with a specific factor. We allow for inferior inputs like low-skilled labor, which do not exist under constant returns, and consider factor complements when more than two factors are present (cf. Diewert (1982, p. 569)). A further general result, which differs from both the 2 × 2 case with constant returns and the Hansson/ Lundahl (1983) approach, states that all factor prices may fall when any single endowment is increased. Finally, and contrary to the literature, we show that our observations do not rule out the Walrasian and Marshallian stability of an equilibrium. Equally important, our findings are robust with respect to global shifts in total factor productivity which raise the economy’s outputs beyond private returns. The paper is organized as follows: Section 2 provides our major results on the existence of non-standard adjustments to endowment changes of a small competitive economy under increasing marginal costs. Two computational examples with different parameterizations are presented in Section 3 for the purpose of illustration. In Section 4, stability is shown. Section 5 introduces external scale effects, and Section 6 concludes. 2. A Small-Country Model with Increasing Marginal Costs We consider n > 2 profit maximizing sectors or industries each producing xi > 0 (i = 1, …, n) units of a single output from at least one input. The economy’s total number of inputs is m > 2. Every input shall be used for the fabrication of some good. There are fixed local factor endowments v´ = (v1, …, vm) where vj > 0 for all j = 1, …, m.3 The small, open economy takes world output prices pi > 0 (i = 1, …, n) as exogenous whereas domestic factor prices wj > 0 (j = 1, …, m) are determined endogenously due to factor immobility. We also assume that the minimum cost in each sector i of producing xi output units at factor prices w´ = (w1, …, wm) can be computed from a twice continuously differen tiable cost function Ci : +m+ × ++ → ++ with the following properties satisfied for all (w, xi) +m+ × ++: Cost is a nondecreasing first-order homogeneous and (weakly) concave function of factor prices w. Marginal cost is positive and (at least locally) increasing (because of decreasing internal returns to scale in production).4 The last-mentioned condition will be satisfied, for instance, if the marginal cost curve of a representative firm in a given industry and, hence, the firm’s average cost curve are U-shaped. Then, the profit maximizing output of this firm is bounded from below by the positive output level which minimizes average cost at given factor prices. This output (the so-called efficient scale, Mas-Colell et al. (1995, p. 144)) will always be determined along the upward-bending part of the marginal cost curve and establishes a discrete market-entry barrier for new competitors. Our analysis relies on the postulate that the economy attains an equilibrium state in which all factors are at full employment. Hence, Σ in=1 C wi j (w, xi) = vj for all j, where C wi j is shorthand notation for ∂Ci/∂wj and thus stands for the quantity demanded of factor j in sector i according to Shephard’s Lemma. At the same time, marginal costs shall equal output prices in all sectors i: C xi i (w, xi) = pi. We assume that each industry supports a given number of firms which can operate at least at their efficient scale without loss. This number shall not be affected by small parameter changes. We are thus given m + n model equations. Total differentiation yields: 3 By default, all vectors shall be defined as column vectors. The prime ‘ /’ denotes transposes. 4 We note for a cost function which is continuously differentiable in factor prices that the isoquants of the underlying production function do not allow for linear substitution between inputs. 11 firstly, DChanges is positive definite and, secondly, the diagonal inverse D Pfingsten/Wolff: Pfingsten/Wolff: Pfingsten/Wolff: Factor Factor Factor Supply Supply Supply Changes Changes in Small ininSmall Small Open Open Open Economies Economies Economies 5 55exists number of firms which can operate at positive least at their efficient scale without loss. This definite. positive definite. D ber shall not be affected by small parameterWe changes. We are thus given m + model thethe the present present present context, context, however, however, however, all all entries alln entries along along along thethe diagonal diagonal ofD are Dare are positive. positive. positive. Therefore, Therefore, Therefore, −1 M We define := C −the Cdiagonal D−1of Cof (cf. Gantmacher (1990,and pp. 45-4 ww xw xw define M := Ccontext, − C D Centries (cf. Gantmacher (1990, pp. 45-46)) req ww xw xw firstly, firstly, DD isDpositive isispositive positive definite definite definite and, and, and, secondly, secondly, secondly, thethe the diagonal diagonal diagonal inverse inverse inverse D DDexists exists exists and and and is likewise isislikewise likewise thatand det(M) = 0. Wolff Certainly some technologies are excluded by this assum ions. Total differentiation yields: Papers Finnish Economic 1/2009 –firstly, Andreas Pfingsten Reiner that det(M) = 0.definite. Certainly some technologies are excluded by this assumption. For positive positive positive definite. definite. ample, suppose that no sector permits input5substitution such that Cww i Pfingsten/Wolff: Factor Supply Changes in Small Open Economies –1, the existence of Dxw regularity oftwo M ismore necesample, that no sector input such that Cww is require aare null −1 −1 −1 (cf. Also suppose that thesubstitution cost structures of or sectors evenma iden We We We define define define MM := M := C := CC −permits C −− CCxw D DC CCxw (cf. Gantmacher Gantmacher Gantmacher (1990, (1990, (1990, pp. pp. pp. 45-46)) 45-46)) 45-46)) and and and require require Cww Cxw dw suppose dv ww ww ww xw xwD xw(cf. = , −1 C −1 C (1) sary and sufficient for a unique solution of (1) case C D will not have full rank. Then, since M = −C D xw xw that that that det(M) det(M) det(M) = = 0. = 0. Certainly 0. Certainly Certainly some some some technologies technologies technologies are are are excluded excluded excluded by by this by this this assumption. assumption. assumption. For For For exexexAlso that the cost structures of xw two or more sectors are even identical, in wx C D dx suppose dp in terms changes in factor rents w and the present xw context, however, all entries along the that diagonal ofof D positive. Therefore, regularity of Mare will be violated. Basically, however, our regularity assump ample, ample, suppose suppose suppose that nono sector nosector sector permits permits permits input input input substitution substitution substitution such that that that Cww CCww is sector isnull aanull matrix. matrix. −1 matrix. ww case Cxw Dample, Cxw willthat not have full rank. Then, since such Msuch = −C Dais−1 Cnull xw–1 xw , the assu outputs x.6 In all, due to det(M) ≠ 0, M exists −1 nates borderline singular cases ofis little economic significance. Given the ex Also Also Also suppose suppose suppose that that that the the the cost cost cost structures structures structures of of two of two two or or more or more more sectors sectors sectors are are are even even even identical, identical, identical, in in which in which which firstly, D is positive definite and, secondly, the diagonal inverse D exists and likewise ducing as x and p the vectors of sector outputs andwill output prices, Basically, respectively, regularity ofcase M be violated. however, our regularity assumption onlyofel introducing p the vectors of sector out−1 −1 −1 C will −1 −1 −1 C ,athe and the following comparative-statics responses the regularity of M is necessary and sufficient for unique solution case case C C C D D D C C will will not not not have have have full full full rank. rank. rank. Then, Then, Then, since since since M M = M −C = = −C −C D D D C C , , the the assumed assumed assumed nas x and xw xw xw xw xw xw xw xw xw xw xw xw n k k 1 , . . . , C n ) and definite. with matricespositive C := = nates ), C := (Cxcases xw ww and puts output prices, respectively, and wi wregularity xfactor w k=1 Cww k=1 (C to changes in therents world market prices p6 and nan 1w j regularity changes in w significance. and sector outputs x. Inthe all, due to det(M) borderline singular of little economic Given existence of = D regularity ofwith of M ofM will Mwill will be be violated. be violated. violated. Basically, Basically, Basically, however, however, however, ourour our regularity regularity regularity assumption assumption assumption only only only elimielimielimin n k k i 5 −1 −1 −1 −1 C : = Σ C = Σ (C ), C : = tional endowments v result (cf. Hadley (1974, diag(Cxi xi ). matrices and the following comparative-statics responses to changes in the world ww w w w w xw nates nates nates borderline borderline borderline singular singular singular cases cases cases of of little of little little economic economic economic significance. significance. significance. Given Given Given the the the existence existence existence of of D of D D , , , =1 Cixw We define M := C Cxw pp. 45-46)) requiresolution of (1) in termm j of(cf. ww − k =1 kD the regularity MGantmacher is necessary (1990, and sufficient for and a unique (C 1 , …, C n ) and D : = diag (C i ).5 −1 −1 −1 pp.and 107–109)): national endowments v result (cf. Hadley (1974, pp. 107-109)): w x n w x ixthe the regularity regularity regularity ofkof M of M M is is necessary is necessary necessary and and sufficient sufficient sufficient for for a unique aa unique unique solution solution solution of of (1) of (1) (1) in in terms in terms terms of ofof−1 i the 1det(M) 6 for that x an = 0. Certainly some in technologies are excluded byand this assumption. For exWe can verify from substitution matrix C whether inputs changes factor rents w and sector x.x. all, due to det(M) =exists 0,exists M ex two outputs ww 66 In −1 −1 We industry’s can verifyHicksian from an industry’s Hicksian changes changes changes in in factor infactor factor rents rents rents ww and wand and sector sector sector outputs outputs outputs x.6x. In In all, Inall, all, duedue due to to det(M) todet(M) det(M) = = 0, =0, M 0,M M−1 exists −1 −1 −1 dw that C Ma null matrix. −M Cxw D k suppose that no sector permits input substitution such is ww j, i = j, areample, complements or substitutes. The associated matrix element will come (2) = substitution matrix C w wand whether two i comparative-statics the following comparative-statics responses changes the world market (2) and and and theinputs the the following following following comparative-statics comparative-statics responses responses responses toto to changes tochanges changes in in the inin the the world world world market market market prices prices prices p pp pric dx −D−1 Cxw M−1 D−1 + D−1 Cxw M−1 Cxw D−1 and j,case i ≠ j,and are complements orsign substitutes. The Also that thea cost structures of two or more are even identical, in107-109)): which and and national national national endowments endowments endowments v interpretation result vvresult result (cf.(cf. (cf. Hadley Hadley Hadley (1974, (1974, (1974, pp.pp. pp. 107-109)): 107-109)): egative in the firstsuppose take positive inand the second. This and national endowments v sectors result (cf. Hadley (1974, pp. 107-109)): out nega Consequently: associated matrix element will come −1 −1 C ,−1the −1 −1 −1 −1 −1 −1 −1 case C D C will not have full rank. Then, since M = −C D assumed xw of the xw note −M es over to the elements already dwdw dw Cww . We MM M −M −MCxw CCD D−1 dvdv dv xwaggregate substitution matrix xw xwD ∂xxw sign −1 −1 −1 −1 (2)(2) (2) = . . .dv tive in the first case and take adw positive in== −1 . M −M C D (3) = −D C M . −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 −1 xw xw dx dx −D −D −DC C Cxw M Msectoral D DD+ D ++DDCxw CC M MCelimiCCxw D D dpdp dp Basically, semi-definiteness . xw xwD regularity of MThis will beto violated. however, regularity assumption only xw xwM xw xwM ∂v =dx (2) negative Cww is negative due the each thesemi-definite, second. interpretation carries over to our of −1 + D−1 C M−1 C dx Consequently: −D−1 Cxw M−1 D−1 1/C i ).dpTherefore −1D xw −1 xw Recall that D has a positive diagonal (with elements k Consequently: Consequently: xi xi nates borderline cases ofsubstitution little economic significance. Given the, existence of D , the elements ofsingular the aggregate maitution matrix Cww (cf. Diewert (1982, p. 567)). Positive or negative entries to Cxw Rybczynski effects ∂x/∂v will always possess the same sign as the corresp ∂x∂x ∂x trix Cwware . We note that inputs, Cand is −1 −1 −1 (1) −1 −1 ww Consequently: the regularity ofalready M isornecessary sufficient for Consequently: a to unique solution ofC in terms of (3)(3) (3)negative == −D −D −D CCxw M M.−1 .. ise, reveal that there superior inferior respectively, the ∂v making of xwM −1= to −C M . Formally, xw introducing as O the null matrix of appropriate ∂v ∂v xw semi-definite, due to the negative semi-6 −1 in factorofrents w and outputs all, due to det(M) = −1 −1In i iexists i ). ∂x ticular good.changes The intensity sectoral scalesector effects isthat measured the diagonal −1 0, M −1 Recall Recall Recall that that Dx. DD−1 has has has aalong positive aProposition apositive positive diagonal diagonal diagonal (with (with elements elements elements 1/C 1/C 1/C ). Therefore, ). Therefore, Therefore, the the respective respective respective xi x.xi x ix ix ii definiteness of each sectoral matrix All Rybczynski ∂x/∂v the will come out positive (3) substitution = 1.(with −D C (3) xw Mderivatives ∂v Rybczynski Rybczynski effects ∂x/∂v ∂x/∂v ∂x/∂v will always always possess possess the the same same same sign sign sign as as the asthe the corresponding corresponding entries entries entries and following comparative-statics responses to changes in−1always the world prices pcorresponding will 7possess will If we had assumed constant returns to scale, DRybczynski would beeffects aeffects null matrix. Then (1) themarket C k the(cf. Diewert (1982, p. 567)). Positive or −C M > O. w w xw toD to −C to −C −C M M . Formally, . . Formally, Formally, introducing introducing as as O asO the Othe the null null null matrix matrix matrix of of appropriate ofi appropriate appropriate dimension: dimension: dimension: −1 xwhas xw xwM negative to CxwRecall ,v likewise, reveal that that a(1974, positive diagonal (with elements 1/C ). Therefore, the respec national endowments result (cf. Hadley pp.introducing 107-109)): d correspond and to (5.1) inentries Diewert/Woodland (1977) and (A9) in Recall Jones/Scheinkman xi xiand This proposition provides a necessary sufficient that D–1 has a positive diagonal (withcondition for an are or inferior there superior inputs, respectiveProposition Proposition Proposition 1. 1. All 1. All All Rybczynski Rybczynski Rybczynski derivatives derivatives derivatives ∂x/∂v ∂x/∂v ∂x/∂v will will will come come come out out out positive positive positive if, if, and if, and and only only only if,supply. if, if, ent i a). ∂x/∂v always possess the same sign the sector outputs as response to an increase any corresponding single factor T ) as well as to (6) in Chang (1979) and Rybczynski (48)-(49) in effects Woodland (1982, Section 4.7). ewill lements 1/C theasinrespective x ixi In Therefore, M The −1 −1 −1 7O. 7−1 7 Cxw D−1 M−1 good. −M dv ly,todw themaking of a particular in−C −C −C M M > O. > > O. xwxw xw −1 intuition is that scale disadvantages on the sectoral level generate increasi = (2) . R ybczynski effects ∂x/∂v will always possess to −Cxw M . Formally, introducing as O−1the null matrix of appropriate dimension: −1 C effects −1 + D−1 C M−1 C of sectoral scale measured dx which −D M−1 is This D Dasand dpspace. e note for a cost tensity function is continuously differentiable inThis factor pricesthe that the isoquants ofthe costs ina the economy’s output Fromforaentries normative xw xw xw This proposition proposition proposition provides provides provides necessary aasign necessary necessary and and sufficient sufficient sufficient condition condition condition for for an an an increase increase increase in in all in all all then same corresponding toviewpoint, along the do diagonal If we had assumed derlying production function not allowofforD. linear substitution between inputs. –1 specialization strategies in favor offactor selected industries are less rewarding Proposition 1.outputs All Rybczynski derivatives ∂x/∂v will come out positive if, and onl sector sector sector outputs outputs as as aasresponse a–C aresponse response to to an to an increase an increase increase in in any in any any single single single factor factor supply. supply. supply. The The The underlying underlying underlying ´ M . Formally, introducing as O the null x w Consequently: returns to scale, would beintuition a null maubscripts attachedconstant to C again represent partial D derivatives. inputs canappropriate be across sectors, i.e., “if [. . opportunity .] opportunity the isoquants are M−1 7is that intuition intuition isisthat that scale scale scale disadvantages disadvantages disadvantages onre-allocated on the onthe the sectoral sectoral sectoral level level level generate generate generate increasing increasing increasing opportunity matrix of dimension: −C > O. xw trix. Then (1) would correspond to (5.1) in (Ylönen (1987, p. From 216)). Examples highlighting the(incomplete) range of this result ∂x costs costs costs in in the in the the economy’s economy’s economy’s output output output space. space. space. From From a normative aa normative normative viewpoint, viewpoint, viewpoint, then, then, then, (incomplete) (incomplete) −1 (3) = in−D Cxw M−1 . Diewert/Woodland (1977) This and∂v(A9) Jones/ specialization specialization specialization strategies strategies strategies in in favor in favor favor of of selected of selected selected industries industries industries are are are less less less rewarding, rewarding, rewarding, provided provided provided that that in proposition provides a necessary and sufficient condition for an increase Proposition 1 All Rybczynski derivatives ∂x/∂v that 6 C −1 −1 −1 Scheinkman (1977) as well as to (6) in Chang In the terminology of the implicit function theorem, the Jacobian determinant C –1 flat” inputs inputs inputs cancan be be be re-allocated re-allocated re-allocated across across sectors, sectors, sectors, i.e.,i.e., “if“if “if [. . [..][.and . the ..].] the the isoquants isoquants isoquants are are relatively relatively flat” flat” −1 has a positive iacross will come out positive if, only if, are –C ´x wrelatively M outputs as acan response to an increase ini.e., any supply. Recall that D(48)–(49) diagonal (with elements 1/C Therefore, thesingle be nonzero. Both w and x can then berespective viewed factor as local functions of (v,The p), i.e.underl functions xi xi ). (1979) and in sector Woodland (1982, Sec O.7Examples (Ylönen (Ylönen (Ylönen (1987, (1987, (1987, p. p. 216)). p.>216)). 216)). Examples Examples highlighting highlighting highlighting thethe the range range range of of this of this this result result result areare are offered offered offered in inin in some neighborhood of the economy’s equilibrium state. ishowever, that scalethe the sectoral levelentries generate increasing opportu tion 4.7). In the ∂x/∂v presentintuition context, alldisadvantages Rybczynski effects will always possess same sign ason the corresponding 7 C ww All matrix and vector inequalities shall hold element-wise. Cxw CCxw ww xw CCww In positive. In the Inthe the terminology terminology terminology of the ofofthe the implicit implicit implicit function function function theorem, theorem, theorem, thethe the Jacobian Jacobian Jacobian determinant determinant determinant will −1 . Formally, C xw will will along the diagonal are CCxw D DD costsofinDthe space. From aprovides normative viewpoint, then, (incompl xw toentries −Cxw M introducing aseconomy’s O the nulloutput matrix ofproposition appropriate dimension: This a p), necessary and be be nonzero. be nonzero. nonzero. Both Both Both w and w w and and x can x x can can then then then be be viewed be viewed viewed as local as as local local functions functions functions of (v, of of (v, p), (v, i.e. p), i.e. functions i.e. functions functions which which which are are defined are defined defined Therefore, firstly, D is positive definite and, secspecialization strategies in favor of condition selected industries are lessin rewarding, for all sector provided in some ininsome some neighborhood neighborhood neighborhood ofsufficient the ofof the the economy’s economy’s economy’s equilibrium equilibrium equilibrium state. state. state.an increase –1 exists ondly, the diagonal inverse Dderivatives and isand Proposition 1. All Rybczynski ∂x/∂v will comeshall out positive if, and only if, 7 77 AllAll matrix Allmatrix matrix andand vector vector vector inequalities inequalities inequalities shall shall hold hold hold element-wise. element-wise. element-wise. outputs as a response to an increase in any sininputs can be re-allocated across sectors, i.e., “if [. . .] the isoquants are relatively fl likewise M−1positive −C > O.7 definite. gle factor supply. The underlying intuition is xw −1C´ (cf. GantWe define M : = Cww – C D (Ylönen (1987, p. 216)). Examples highlighting the range of this result are offere xw x w that scale disadvantages on the sectoral level macher (1990, pp.provides 45–46))a and requireand that This proposition necessary sufficient condition for an increase in all 6 66 generate increasing opportunity costs in theC C ww xw 6 det(M) ≠ 0. some technologies In ofany the implicit functionsupply. theorem,The the Jacobian determinant sector outputs Certainly as a response to the an terminology increase inare single factor underlying economy’s output space. From a normative Cxw D excluded by this assumption. For example, supbe nonzero. Boththe w and x can viewpoint, then be viewedthen, as local functions of (v,specialization p), i.e. functions which are de (incomplete) intuition is that scale disadvantages sectoral level generate increasing opportunity pose that no sector permits input on substitution strategies in favor then, of selected industries are less costs theCeconomy’s space.suppose From that a normative viewpoint, (incomplete) suchinthat matrix. Also ww is a null output 7 in some neighborhood of the economy’s equilibrium state. All matrix and vector inequalities shall hold element-wise. rewarding, provided that inputs can be re-allo- the cost structures of two or more sectorsindustries are specialization strategies in favor of selected areacross less rewarding, provided cated sectors, i.e., “if [...]that the isoquants even identical, in which case C xwD −1C ´x w inputs can be re-allocated across sectors, i.e., “if [.are . .] relatively the isoquants relatively flat” flat” are (Ylönen (1987, p. 216)). Exwill not have full rank. Then, since M = (Ylönen (1987, Examples highlighting – C D–1 C´ , p. the216)). assumed regularity of M will the range of this result are offered in xw x w 6 In the terminology of the implicit function theorem, the be violated. Basically, however, our regularity Cww Cxw 6 will In the terminology of the implicit function theorem, the Jacobian determinant will be nonzero. Jacobian determinant assumption only eliminates borderline singular Cxw D Bothofw(v, and can functions then be viewed local functions of (v, p), of little economic becases nonzero. Both w and x can significance. then be viewed Given as local the functions p),x i.e. whichasare defined i.e. functions which are defined in some neighborhood of the economy’s equilibrium state. 5 Subscripts 7 All matrix and vector inequalities shall hold elementAll matrix and vector to inequalities shall holdpartial element-wise. attached C again represent derivatives. wise. in some neighborhood of the economy’s equilibrium state. 7 12 Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff amples highlighting the range of this result are offered in the next section. Any such example must allow for input substitution in at least one production sector, as we shall now prove. We will make use of the following observation: Lemma 1 If no technology supports input substitution, then Cxw > O. Proof Consider the cost function Ci (w, xi) of an arbitrary sector i. By definition of this function and because of Shephard’s Lemma, Ci (w, xi) = ΣjwjC wi j (w, xi) for all positive factor prices and outputs. Hence, C xi i (w, xi) = ΣjwjC wi j xi (w, xi). As input substitution is not permitted, the factor demands C wi j (w, xi) and, hence, the second-order derivatives C wi j xi (w, xi) are all independent of w. Now suppose, per absurdum, that Cwk xi (w, xi) < 0 for some input k. Then, for every wk that is sufficiently large, we would obtain C xi i (w, xi) < 0, which contradicts the fact that marginal cost is always positive. Finally, notice that Cxi wk (w, xi) = Cwk xi (w, xi) according to Young’s Theorem. Remark 1 Suppose that no technology supports input substitution. Then the matrix inequality –C´x wM–1 > O cannot be satisfied. Proof As no technology permits input substitution, C iw w = O for all sectors i. Hence, by definition, C ww = O. This implies M = –Cxw D−1 C´x w. Now let E : = (eij) denote the m × m identity matrix such that E = MM−1 = CxwD−1 (–C´x wM–1), where Cxw > O by Lemma 1. Therefore, if all entries to the matrix product in brackets were positive, eij = 0 (i ≠ j) would require that the entire row i of Cxw vanishes, contradicting eii = 1. Consequently, not all elements of –C´x wM–1 can be positive at the same time. Our remark confirms that scale effects do not matter, i.e., the standard Rybczynski outcome persists, if input substitution is ruled out in all industries. In this case, expanding the economy’s outputs altogether would require more of every, and not just one, input. We now briefly address the adjustments in factor prices. In the standard Heckscher-Ohlin framework of two commodities and factors with constant returns to scale, the price of the factor of which an extra supply has become available will decrease whereas the other factor price will increase (cf. Woodland (1982, p. 79)). In our model economy, factor price responses to endowment changes are given by M–1 (cf. equation (2)). By definition, M (and hence M–1) is negative definite and will thus always possess a negative diagonal.8 Together with the examples in the following section this proves: Proposition 2 The own-price effects of arbitrary supply shocks are normal, whereas for i ≠ j the adjustments ∂wi /∂vj may be of either sign. In particular, and different from both the standard set-up and the Hansson/Lundahl (1983) approach with homogeneous production functions, all factor prices may decrease as any single endowment increases. A definite statement can be made in the special case of an economy that produces its outputs from just two inputs. This statement is based on the occurrence of inferior factors like, e.g., low-skilled labor: Remark 2 Suppose there are two inputs to production in all of the economy. Also suppose that at least one industry uses an inferior factor. Then, it follows from the inequality –C´x wM–1 > O that the factor price responses ∂wi /∂vj (i ≠ j) cannot be normal. Proof To begin with, introduce as e the first ndimensional unit vector, i.e. e´ = (1 0 ... 0). Assume that –C´x wM–1 > O, and hence –M–1 Cx w > O for the− product transpose. Thereby, M−1b > o, where b : = –Cxwe holds the negative of the first column of Cxw (and o stands for the null vector of length 2). Without loss of generality, suppose that this column’s first entry is negative, indicating an inferior input in sector one. Hence, b1 > 0, while b2 < 0. At this point, recall that M–1 is negative definite and thus has a neg8 Note that r´ Mr = r´ C r – r´ C D–1 C´ r < 0 for all ww xw xw r ≠ o of length m, since Cww is negative semi-definite and –1 D is positive definite (with C´ xwr possibly equal to the null vector). Hence, r´ Mr < 0 by the assumed regularity of M. (Cf. Diewert/Woodland (1977, p. 392) for a similar argument in the context of constant returns to scale.) 13 Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff ative diagonal. Consequently, we conclude from M–1 b > o that the second element in the first row of M–1 takes a negative value (and so does the first entry to the second row by the symmetry of M–1). Proposition 2 and, in particular, Remark 2 are less surprising if residual profits are accounted for. As a consequence of decreasing returns and marginal cost pricing, the economy can generate positive profits. These profits also can be maintained since we assume a given number of firms per industry, e.g., when low-level market entry may not cover average cost. Then, profits possibly rise in each single industry if a factor supply shifts upwards: Corollary 1 Consider again the n × 2 economy presented in Remark 2. Hence, suppose that both factor prices decrease in response to an expansion of a single endowment. Then all sectors will enjoy higher profits. Proof Let Πi (pi, w) : = maxxi > 0 {pi xi – Ci (w, xi)} denote the profit function of an arbitrary sector i. By Hotelling’s Lemma, Π wi j (pi, w) = –C wi j (w, xi) for both factor prices (j = 1, 2). Total differentiation of Πi (pi, w) with respect to w thus gives dΠi (pi, w) = –C wi 1 (w, xi) dw1 –C wi 2 (w, xi) dw2. As at least one of the two factor demands C wi j (w, xi) in sector i must be strictly positive, we conclude that the profit of sector i increases when both factor prices fall. It is important to note that the division of profits depends on firm ownership which we have not modeled, as we did not include a domestic or international capital market. Therefore, the consequences of profits on the distribution of incomes within the economy and, potentially, outside must remain indeterminate. However, given that world-market output prices are considered as exogenous, the economy’s Rybczynski derivatives will not be affected. In view of the standard reciprocity relation (cf. Samuelson (1953/1954)), one might presume that non-Rybczynski responses of outputs to endowment changes always go along with non-StolperSamuelson effects of output price variations on factor prices. As to these effects, however, the 14 distribution of residual incomes, maybe to omitted factors, becomes an essential issue. Yet, a complete exploration of the comparative statics associated with output price variations and, in particular, of the Stolper-Samuelson derivatives under decreasing returns to scale is beyond the scope of the present paper. 3. Computational Examples We now present two computational examples of technologies and related cost functions, respectively, which shall further illustrate our results under different scenarios. Our first example is that of a two-sector economy with two inputs. The sectoral cost functions correspond to a production process with a fixed factor intensity in one sector and to a substitutional technology in the other. We consider different equilibrium states in which one input can also be inferior. In all three states, all Rybczynski derivatives come out positive, along with both standard and nonstandard factor price responses. We then assume, in our second example, that sector 2 employs a third input that is specific to this sector. We consider two different parameterizations of the sectoral cost function which illustrate the occurrence of complementary and inferior inputs. Once again, all Rybczynski derivatives are positive. In comparison, a standard Ricardo-Viner two-sector model with sectorspecific inputs and constant returns (cf. Jones (1971)) predicts that a rise in the supply of a specific factor in one sector will increase this sector’s equilibrium output, while the other sector will shrink. Also in more general models, where strictly sector-specific factors are replaced by mobile so-called ‘extreme’ inputs, not all Rybczynski derivatives can be positive at the same time (cf. Ruffin (1981) and Jones/Easton (1983)). In our second example, again, not ev ery factor price response is normal. Example 1 Let n = m = 2 and consider both the cost function C1 (w1, w2, x1) = (0.1w1 + 0.05w2) x111.26, which comes from a production process with a fixed factor intensity, as well as the cost function C 2 (w 1, w 2, x 2) = w 1 x 112. 2 + 2√w 1w 2 x 112. 1 – w2x112. 3, which belongs to a substitutional 9 Pfingsten/Wolff: Factor Supply Changes in Small Open Economies Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff results, depending on the level of η: Pfingsten/Wolff: Changes in Small Openlengthy Economies calculations (to be obtained 9from the technology, overFactor someSupply domain in the neighbor1. Letof η= . We find: assumed equilibrium authors upon request) lead essentially to the subhood the1.0economy’s results, depending on the level of η: state w1 = 1.5, w2 = 1 0.408 and x1 = 1, x2 = η. Some sequent −0.272 0.126 2.098 0.066 0 results, on the level Cwwdepending = , ofCη: xw = 0.408 −0.612 1. Let η =1.0 . We find: M = Cww = −18.900 −0.127 , −0.272 0.408 −0.127 −0.682 , 0.408 −0.612 2. Let η =1.15 . Then: M −18.900 −0.127 = , −0.127 −0.317 Cww = 0.476 −0.682 0.476 −0.714 , 2. Let η =1.15 . Then: 0.245 , −22.906 = M Cww = −0.317 0.476 0.245 −0.775 , 0.476 −0.714 3. Let η =1.5 . This gives: M = Cww = −22.906 0.245 −0.425 0.638 0.245 , −0.775 0.638 −0.957 , 3. Let η =1.5 . This gives: −33.215 = M Cww = 1.465 , −0.425 0.638 1.465 −1.045 , 0.638 −0.957 M−1 = Cxw = −1 M 0.063 −0.053 0.010 0.126 0.010 2.098 −1.468, 0.063 0.047 −0.053 = Cxw = , 0.047 0.010 0.010 2.145 −1.468 0.126 , 0.063 0.011 D= Cxw = −1 −0.044 −0.014 0.126 0.063 −0.014 , D= −0.065 D= . . 0 . . . 0.006 0.091 0.111 0 0.206 , 0.049 0.006 0.083 = 0.066 0 0.094 , 0.043 0 0.206 M−1 = 0.006 0.083 −Cxw 0.094 0.043 0.066 0 D= , 0 0.154 , −0.032 −0.045 = , M Cxw = = 0.066 −Cxw M−1 , −1.294 2.237 −Cxw M−1 0.126 2.145 −0.014 −1.294, 0.063 0.011 M−1 = , 0.239 0.006 0.091 −Cxw M−1 = 0.066 0 0.111 D= , 0.049 0 0.239 , −0.044 −0.014 −1 M = , Cxw = 0 0.007 0.070 = 0.066 0 0.069 , 0.034 0 0.154 −Cxw M−1 0.126 2.237 −0.045 −1.020 , 0.063 −0.065 D= −1 is positive.Consequently, ∂x to −C i /∂vj is positive In all threecases, every entry xw M −33.215 −0.032 1.465 −0.045 0.007 0.070 −1 −1 , Man =increase in any single , −C = . M i,j= = 1,2. In other words, xw Mendowment for all factor 1.465 −1.045 −0.045 −1.020 0.069 implies 0.034 an increase in all sector outputs, i.e., no sector will shrink. At the same time, in the first −1 is positive. In all both three factors cases, every entry to and −Cxw Mmatrix Consequently, ∂xi /∂vfactor j is positive case, are superior the M−1 exhibits the standard price cases, every entry –C ´x wM–1 is forInallalli,jthree =In1,2. In other words, increase in inputs any single factor implies an first exExample 2 This endowment is an outgrowth of our responses. the second case, thetoan superiority of is maintained. However, all factor positive. Consequently, ∂x /∂v is positive for all ample. We takesame n = 2,time, m = 3. Thefirst first sector i j i.e., no sector −1 increase in all sector outputs, will shrink. At the in the prices will now decrease since all elements of M are negative (cf. Proposition 2). This i, j = 1, 2. In other words, an increase in any sin- shall only use factors 1 and 2 and shall thereby case, both factors are superior the matrix M−1 in exhibits the standard factor price holds again in the third case, where factor 2 is the second industry (cf. Remark gle factor endowment implies anand increase in allinferior once more possess the same technology and responses. In the case,will the shrink. superiority of inputs is maintained. However, factorHowever, sector outputs, i.e.,second no sector At the 2). cost function, respectively, as all before. same in the first case, both areofsuthe second sector employs a pricestime, will now decrease since all factors elements M−1now are suppose negative that (cf. Proposition 2). This Example 2. ThisMis–1 exhibits an outgrowth of our first example. We take n = 2, m = 3. perior and the matrix the standard specific third input such that sectoral holds again in the third case, where factor 2 is inferior in the second industry (cf. Remarkminimum The first sector shall only use second factors case, 1 andthe 2 and shall once local more representation possess the of the factor price responses. In the cost hasthereby an extended 2). 11. 2 11. 1 2 superiority of inputs is maintained. However, all form C (wHowever, same technology and cost function, respectively, as before. suppose that1 w2 x 2 – 1, w2, w3, xnow 2) = w 1 x 2 + 2√w 11. 3 11. 1 factor prices will now decrease since all elew x + (σ√w w + τ√w w + ψw ) x . The 2 example. 1 minimum 2take 2 cost 3 m 2 sectoral 2. employs This is an outgrowth our first We 2, =3an 3. 2 n = the Example second sector a specific thirdofinput such that has ments of M–1 are negative (cf. Proposition 2). economy’s equilibrium position 1.1 shall be at√ 2 1.2 The first sector shall only use offactors 1 and more − x = 1, extended form C 2(wand w2shall , w3 ,atxthereby ) = w1once x + 2 wpossess 1 ,tained 2w 1 w2 x2 the This holdslocal againrepresentation in the third case,the where factor and 1 = 1.5,2w2 = 1, w3 = 1.5 1 √ √ 1.3 1.1 same technology and as before.The However, now suppose x2 inferior + (σ w τcost w2function, w3industry + ψw3respectively, ) x(cf. The economy’s equilibrium position shallthat be parame2w in1 wthe x2 = 1.5. following are interesting 2is 2 + second 2 . Remark 2). at sector terizations of σ,following τminimum and ψ are (computational the second employs third such that cost has an details attained w1 = 1.5, w2 = a1,specific w3 = 1.5 and input x1 = 1, x2 = 1.5.sectoral The interesting √ can be acquired from the authors): 2 1.2 extended local representation of the form C (w , w , w , x ) = w x + 2 w w x1.1 − 1 2 can 3 be 2 acquired 1 2 from the1 authors): 2 2 parameterizations of σ, τ and ψ (computational details √ √ 1.3 1.1 w2 x2 + (σ w1Factor w2 + τSupply w2 wChanges ) xSmall economy’s be Pfingsten/Wolff: Open Economiesequilibrium position shall 10 3 + ψw3in 2 . The 1. Let (σ, τ, ψ) = (−0.1, 1.5, −0.54). We get: attained at w1 = 1.5, w2 = 1, w3 = 1.5 and x1 = 1, x2 = 1.5. The following are interesting 0.987 , D= 0.288 0.516 parameterizations τ and ψ (computational details can be acquiredfrom the authors): 0.126 2.179 −0.399 of σ, 0.638 −0.026 Cww = 0.638 −1.674 0.478 , M −22.164 −9.231 −0.279 −0.279 0.364 −0.296 = −9.231 −Cxw M−1 = −6.149 0.003 0.005 0.364 , 0.003 . Cxw = 0.063 1. Let (σ, τ,−0.026 ψ) = (−0.1, 1.5,−0.293 −0.54). We get: 0.478 M−1 = 0 −0.172 0.288 0.516 0.026 −0.659 −1.083 0.066 0 0 0.221 −1.083 , −5.199 , 15 −0.399 0.638 Cww = 0.638 −1.674 −0.026 0.478 , 0.126 2.179 Cxw = 0.063 0.987 , D= 0.066 0 0 0.221 0 0.026Reiner Wolff −0.026 Papers 0.4781/2009 −0.293– Andreas Pfingsten Finnish Economic and M −22.164 −9.231 −0.279 −0.279 0.364 −0.296 = −9.231 −Cxw M−1 = 0.364 , −6.149 0.003 0.005 0.003 0.076 0.050 0.076 M−1 = −0.172 0.288 0.516 0.288 −0.659 −1.083 −0.423 0.638 −0.003 −0.003 0.022 −0.012 Cww = 0.638 −0.990 M = −32.404 0.745 −0.061 −Cxw M−1 = 0.022 , −0.061 0.745 0.023 , −1.052 −0.012 0.023 0.005 0.066 0.095 0.070 0.035 0.053 , −1.083 , −5.199 . 2. Let (σ, τ, ψ) = (−0.01, 0.07, −0.02). Accordingly: 0.516 0.126 2.231 0 0.004 D= 0.119 Cxw = 0.063 −0.016 , −0.032 −0.020 0.119 −1.743 M−1 = −0.020 −1.002 0.066 0 0 0.157 , −1.743 , −84.536 . We find once more again that −Cxw M−1 is element-wise positive. In both cases, factors in our2 model equilibrium prices and We find3 once more again that –C´x wto M–1 ele- that 1 and are complementary inputs theis second industry as indicated by thefactor respecoutputs are always (locally) stable once the ment-wise positive. In both cases, factors 1 and tive negative off-diagonal entries to Cww . (Recall from our notation in Section 2 that market-clearing process operates according to 3 are complementary inputs to the second in1 Cww =2 C + C2ww by and thatnegative C1ww vanishes.) The second case illustrates that princisome plain, yet intuitively appealing, dustry asww indicated theobserve respective the simultaneous occurence an inferior input the same sector is possible if there are off-diagonal entries to Cwwof . (Recall from our2 inples. 1 + C2 and Pfingsten/Wolff: Factor Supply Changes inare Small Open Economies We suggest two standard types of adjustment notation in Section 2 that C = C ww ww notwwallFactor more than two factors. In both cases, factorSupply price responses normal. Pfingsten/Wolff: Changes in Small Open Economies observe that C1ww vanishes.) The second case processes in the factor and commodity markets, illustrates that the simultaneous occurence of an respectively (cf. Mayer (1974)). To begin with, yet intuitively intuitively appealing, principles. 4 Stability yet appealing, principles. that rent variations are proportional inferior input 2 in the same sector is possible if we propose by positive scalars kj to the processes amount ofin excess there are more than two factors.We In both cases, suggest two standard types of adjustment adjustment the factor factor and and com co suggest two standard types of processes in the This Walrasian price-tâtonnenot factor pricesimple responses areWe normal. Theall above cases, as they are, demonstrate input clearlydemand. that non-Rybczynski outcomes markets, respectively respectively (cf. (cf. Mayer (1974)). (1974)). To To begin begin with, with, we we propose propose that that rent rent vv markets, mentMayer shall be complemented in theAcgoods marmay emerge in a standard 2 × 2-setting if increasing marginal costs are assumed. are proportional proportional by by positive positive scalars to the the amount mechanism: of excess excess input input deman deman kets by ascalars Marshallian adjustment are kkjj to amount of cording to Samuelson’s correspondence principle outputs (cf. Samuelson (1947)), however, such evolve in the direction of the difference Walrasian price-tâtonnement shall be complemented in the goods markets by Ma 4. Stability Walrasian price-tâtonnement shall be complemented in the goods markets by aaMa comparative-statics results are meaningful only if between stability world of the equilibrium is guarandemand prices and domestic adjustment mechanism: mechanism: outputs outputs evolve evolve in in the direction direction of of the the difference difference betwee betwe prices (inusually termsthe of marginalwith cost of proThe cases, simple asadjustment they are, demon- supply teed.above The argument, so-called comparative-statics paradoxes were associated demand prices prices and and domestic supply prices (in terms terms of marginal marginal cost of production productio demand supply (in of duction), againprices by some positive factors ofcost pro-of strate clearly that non-Rybczynski outcomes domestic unstable equilibria and would otherwise vanish, has been put forward repeatedly in the by some some positive positive factors of proportionality proportionality Assuming for simplicity simplicity that kkj = =l portionality li. Assuming for simplicity that that may emerge in a standard 2 × 2-setting if inby factors of lli.. Assuming for j literaturemarginal on international (e.g. According Mayer (1974),k9j = l Ide/Takayama (1988,i 1990)). For 9this creasing costs aretrade assumed. i = 1 for all j and i, we obtain: all j and i, we obtain: 9 all j and i, we obtain: reason, it is important to note thatprinciple in our model prices and outputs are to Samuelson’s correspondence (cf. equilibrium factor n n i Samuelson (1947)), however, such comparative- process (4) (4) ẇ = C (w,xxi))to −some vj for all j , i always (locally) stable once the market-clearing operates according plain, ẇjj = Cwwjj(w, i − vj for all j , statics results are meaningful(4) only if stability of i=1 i=1 the equilibrium is guaranteed. (5) The argument, (5) ẋẋi = = ppi − −C Cixi i(w, (w,xxi)) for for all all ii,, (5) i i i xi so-called comparative-statics paradoxes were usually associated with unstable equilibria andLemma where Shephard’s hasShephard’s been used used in in (4). has been used in where Lemma where Shephard’s Lemma has been (4). would otherwise vanish, has been put forward (4). Associatedtrade with the the adjustment adjustment model model (4)-(5) (4)-(5) isis the the following following linear linear approx appro repeatedly in the literature on international Associated with system (cf. (cf. Takayama Takayama (1985, (1985, p.‘·311)) which has been been evaluated evaluated around an equ eq (e.g. Mayer (1974), Ide/Takayama (1988, 9 The dot ’311)) indicates total differentiation with respectaround to system p. which has an ∗ ):note 1990)). For this reason, it is state important time. (w∗∗ , xto ∗ state (w , x ): 16 (6) (6) ẇ w − w∗ ẇ = A w − w∗ ẋ = A x − x∗ ẋ with the Jacobian matrix A defined as: with the Jacobian matrix A defined as: Cww Cww x − x∗ Cxw C xw n ẇj = C ii j (w,evolve xi ) − in vj the for direction all j , stment mechanism: outputs of the difference between world ẇj = i=1 Cw wj (w, xi ) − vj for all j , and prices and domestic supply prices (in terms of marginal cost of production), again i=1 ẋi = pi − Cxii i (w, xi ) for all i , ome positive factors . Assuming for simplicity kj =–liAndreas = 1 for Pfingsten and Reiner Wolff ẋi = piof−proportionality Cxi (w, xi ) forlFinnish i , Economic iall Papersthat 1/2009 9 and i, we obtain: d’s Lemma has been used in (4). the adjustment model (4)–(5) We thus find, unlike Mayer (1974) and Ide/ d’s Lemma hasAssociated been usedwith in (4). n is the following linear approximation system Takayama (1988, 1990), that (seemingly) parai with the adjustment model (4)-(5) is the following linear approximation ẇmodel Cwj (w,isxithe ) − following vj for all jlinear , j = with the adjustment (4)-(5) approximation (cf. Takayama (1985, p. 311)) which has been doxical comparative-statics effects may be obi=1 kayama (1985, p. 311)) which has been evaluated around an equilibrium ∗, x∗): anserved kayama (1985, p. 311)) around equilibrium i been evaluated evaluated around state (w even in well-behaved settings with loẋi which = pi an −has Cequilibrium (w, x ) for all i , i xi cally stable equilibria. The following differ ∗ ẇ beenused w− ences in the approach taken by these authors on re Shephard’s Lemma in w (4). ∗ ẇhas = A w − w (6) ẋ = A x − x∗ the one hand and our model on the other hand ∗ Associated with the adjustment model is the following linear approximation ẋ x − x(4)-(5) appear to be crucial. Firstly, we assume that ian (cf. matrix A defined as: em Takayama (1985, p. 311)) which has been evaluated around an equilibrium with the Jacobian matrix A defined as: prices equal marginal rather than average costs ian matrix A defined as: ∗ ∗ and that firms operate at least at their efficient e (w , x ): Cww Cxw Cww Cxw w. − w∗ A := scale without loss. Secondly, Mayer and Ide/ ẇ (7) A := −C −D = A . Takayama impose several restrictions upon the −Cẋxw −D ∗ xw x−x equilibrium outcomes of their models, followepared to introduce our next proposition: epared to introduce next proposition: the Jacobian A defined as: to introduce our next ing Jones (1968). They thereby neglect inferior Wematrix are our now prepared proposition: inputs and 3. All eigenvalues of A are negative real C numbers. The equilibrium statealso require that an increase in any Cww xw 3. All eigenvalues of A are negative real numbers. The equilibrium state A := . factor price must raise the average equilibrium ble. −Cxw of −D ble. Proposition 3 All eigenvalues A are negative production cost of each commodity. Therefore, ∗, x∗) is real numbers. Therelated equilibrium state (w certain non-obvious cases of technologies and d znow denote an eigenvalue and respectively, of A. Hence, are prepared to introduce our nexteigenvector, proposition: d z denote an eigenvalue and related eigenvector, respectively, of A. Hence, stable. endowment hermore, partition z into two vectors z1 and z2 of suitable length such thatchanges are excluded from their aphermore, partition z intotwoofvectors z2real of suitable such that position 3. All eigenvalues A are znegative numbers.length The equilibrium state to our results, the cases al1 and proach. According z denote an eigenvalue Proof Let λ and x∗ ) is stable. Cww Cxw z1 and re- lowing for non-standard Rybczynski responses Cww Cxw ofz1A. Hence, of industry outputs in otherwise stable equilibria z Azlated = eigenvector, (z1 z2 ) respectively, z z Az = (z1 z2 ) −Cxw −D 2 f. Let λ andAz = z denote an eigenvalue and relatedzeigenvector, respectively, A. Hence, λz. Furthermore, into −Cxw partition −D z2 two vecmust beofamong them. = z C z − z Dz tors z1 and z2 of1 zsuitable such thatz2 of suitable length such that ww 2 length 1 2 two = λ z. Furthermore, partition into vectors z and 1 = z C z − z Dz 1 ww 1 2 2 = λ z z . Cww Cxw z = λz z. 1 5. External Scale Effects (8) z Az = (z1 z2 ) −C −D z2 567)). Also recall xw (1982, p. w is a negative semi-definite matrix (cf. Diewert (cf. Diewert (1982, p. 567)).The Also recall w is a negative semi-definite matrix recent literature on total factor productivity = zwill 1 − z2 Dz2definite, and we may conclude 1 Cww ive definite. Therefore, −D beznegative provides empirical evidence for the existence of ive definite. Therefore, −D will be negative definite, and we may conclude = λ z z . scale effects in terms of knowledge spillovers dicates total differentiation with respect to time. dicates total differentiation with respect to time. between production sectors and in terms of production externalities which are not (cf. Diewert (1982, p. 567)). Also recall that D other D is positive definite. Therefore, −D will be negative definite, and we may within the conclude direct exploitation potential of a sinis positive definite. Therefore, −D will be negagle firm or industry (e.g., Caballero/Lyons The dot ‘·’ indicates total differentiation with respect to time. tive definite, and we may conclude from (8) that (1990), Benarroch (1997), Midelfart/Steen all eigenvalues of A must be real and non-posin/Wolff: Factor Supply Changes in Small Open Economies 12context, a firm which is subject (1999)). In this tive. Regularity of D implies det(−D) ≠ 0, while det(M) ≠ 0 by assumption (cf. Section 2). There to increasing marginal cost appears to operate under constant or even increasing returns to fore ) that all eigenvalues of A must be real and non-positive. Regularity of D implies scale if there are inter-industry shifts in produc) = 0, while (9) det(M) = 0 by assumption (cf. Section 2). Therefore tivity. We now show that our results are robust with respect to a simple class of production ex det(A) = det(−D) det(Cww − Cxw D−1 Cxw ) ternalities. Our analysis once more sticks as closely as possible to the static model of perfect = det(−D) det(M) competition. We can startnot from (cf. pp. Gantmacher (1990,det(A) pp. 45–46)) requires ntmacher (1990, 45-46)) requires = 0. Consequently, zero be the notion that the output xi of det(A) ≠ 0. Consequently, zero can not be an each arbitrary industry i is a function fi (·, E, V) nvalue of A. Thus all eigenvalues of A must be negative reals which is sufficient eigenvalue of A. Thus all eigenvalues of A must of several input factors and of proxies E and V ∗ ∗ w∗ ) to be stable (see Takayama (1985, p. 310)). be negative reals which is sufficient for (x , w ) of activity-based externalities and technical progress, respectively (Caballero/Lyons (1990)). to be stable (see Takayama (1985, p. 310)). thus find, unlike Mayer (1974) and Ide/Takayama (1988, 1990), that (seemingly) As E and V are by assumption out of control of Note that Cww is a negative semi-definite matrix e that Cww is a negative semi-definite matrix (cf. Diewert (1982, p. 567)). Also recall ical comparative-statics effects may be observed even in well-behaved settings cally stable equilibria. The following differences in the approach taken by these on the one hand and our model on the other hand appear to be crucial. Firstly, we that prices equal marginal rather than average costs and that firms operate at least efficient scale without loss. Secondly, Mayer and Ide/Takayama impose several 17 Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff industry i, their respective output elasticities can be locally normalized to equal unity (cf. Caballero/Lyons (1990, pp. 808–809), Basu/ Fernald (1995, p. 169) for a formal exposition), in which case the industry production function has a local representation of the form xi = αhi (·), where α : = EV. From the viewpoint of a single firm or industry, increases in α are perceived as exogenous downward shifts of the (upwardsloping) marginal cost curve. We assume that α is a non-decreasing function of the economy’s aggregate economic activity as measured by the levels of total endowments. Recall that these endowments are at full employment by assumption. They can thus serve as a means of transmission of global knowledge spillovers and localized agglomeration forces across industries. In the literature on new economic geography and on endogenous economic growth, this role is often attributed to the stock of physical capital (Romer (1986)) and to the ‘human capital’ or skill of a typical worker (Lucas (1988)). Then, λxi = h (·) with λ : = 1/α. Hence, λ decreases if external scale advantages have a positive effect on the total factor productivity in sector i. For simplicity, we pretend that this effect is the same in every industry. Now let yi : = λxi for all industries i. Also, assume without loss of generality that λ = 1 in the economy’s initial equilibrium. With this change in notation, our results in Sections 2–4 can all be retained. Furthermore: Proposition 4 The signs of all positive Rybczynski derivatives are preserved under a decrease of λ. Proof Suppose there is an extra supply of resources which generates an aggregate scale effect dλ < 0. By dyi = dxi + xidλ and xi > 0, we conclude that dxi > 0 whenever dyi > 0. Hence, the signs of all positive derivatives ∂yi /∂vj carry over to ∂xi /∂vj. It even turns out that there is more room for a positive output response in all industries to an expansion of endowments, since output xi will also increase if dyi < 0 as long as | dyi | < xi | dλ |. Again, we think that there is nothing ‘paradoxical’ about this result. In contrast, our findings 18 are still intuitively plausible and consistent with a profit-maximizing behavior of firms or industries in a competitive environment. 6. Conclusion The purpose of this paper was to examine the comparative statics of endowment changes in a small open and competitive economy with a finite number of goods and factors. We assumed that this economy is exposed to diseconomies of scale, and thus to increasing marginal costs, within each industry. This assumption was motivated by a critical assessment of the standard replication argument for constant returns, both from a theoretical and an empirical perspective. Scale disadvantages create increasing opportunity costs in the economy’s output space. From a normative viewpoint, then, (incomplete) specialization strategies in favor of selected industries are less rewarding, provided that inputs can be re-allocated across sectors. Common intuition thus suggests that all production sectors should benefit from an extra supply of any scarce resource. We proved as our major result that this conjecture, although in conflict with Rybczynski’s theorem, can hold true, indeed, if the production technologies permit input substitution. In contrast to the literature, we showed that our result is fully compatible with the Walrasian and Marshallian stability of the under lying equilibrium. Our findings also turned out to be robust with respect to global shifts in total factor productivity which raise the economy’s outputs beyond private returns. As the Rybczynski theorem was developed in the context of the Heckscher-Ohlin or factor proportions theory of international trade, empirical tests of this theory in the literature may shed some light on the relevance of the nonRybczynski responses we have derived. A seminal book is Leamer (1984). Alas, he argues that it is “... wildly optimistic to recover the Ryb czynski coefficients from data on trade and endowments by a regression of trade on a subset of excess factor supplies” (Leamer (1984, p. 159)). Therefore, he opts for an estimation of a reduced-form model. Unfortunately, estimates Finnish Economic Papers 1/2009 – Andreas Pfingsten and Reiner Wolff of the Rybczynski coefficients cannot be easily constructed from this model. 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