Problem Characteristics
1.
2.
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7.
Is the problem decomposable?
Can solution steps be ignored or undone?
Is the universe predictable?
Is a good solution absolute or relative?
Is the solution a state or a path?
What is the role of knowledge?
Does the task require interaction with a
person?
1
Production system characteristics
Monotonic: execution of a rule never prevents
the execution of other applicable rules
 Non-monotonic: without this property
 Partially commutative: if application of a
particular sequence of rules transforms state x
into state y, then any permutation of those
rules that are allowable, transforms x into y
 Commutative: monotonic + partially
commutative

2
Problems and production system
monotonic
Non-monotonic
Partially
Theorem
Robot
commutative
proving
navigation
Non-partially
Chemical
backgammon
commutative
synthesis
3
Problems and production system
Partially
monotonic
Non-monotonic
Ignorable
Recoverable
commutative
Non-partially
commutative
Irrecoverable
Irrecoverable
Unpredictable
4
Sample problems - 8-puzzle
5
Sample problems - 8-puzzle
6
Sample problems - 8 queens
7
Sample problems - 8 queens
8
Sample problems - 8 queens
9
Sample problems - Cryptarithmetic
10
Sample problems - Cryptarithmetic
11