Introduction to Debates
CS5800 Algorithms
Instructor: Karl Lieberherr
Teaching Assistant: Zhengxing Chen
Based on Ahmed Abdelmeged’s Dissertation
Approach
• We introduce debates with two sets of
slides
– The first set covers debates between two
students, based on semantic games.
• Logical formulas
• Games based on logical formulas
• Evaluation based on merit graphs
– The second set (these slides) extends debates
to involve the entire class.
Review
• Semantic games for interpreted logical
formulas
Semantic Games (SGs)
for interpreted formulas
• A semantic game for a given claim⟨φ, A⟩
is a game played by a verifier and a
falsifier, denoted SG(⟨φ, A⟩, verifier,
falsifier), such that:
– A |= φ <=> the verifier has a winning strategy
for φ.
4
5
Introduction
• 3 students form a team
– Teams will be carefully selected
– In first class we have ad-hoc teams.
• 2 forms of debates
- Intra-team
- Inter-team
Intra-team Debate
• In a team, every 2 team members have
one debate. So there are only 3 debates
for each small round-robin tournament.
Forced players are chosen randomly/
• Team member with fewest number of
losses wins.
– It is possible that all three team members win!
Intra-team Debate
• Two sides for any given claim:
- Verifier (believes claim is true)
- Falsifier (believes claim is false)
• 2 engaged team members choose sides,
while the 3rd team member plays as an
admin (checking the game rules)
• One must be the forced falsifier/verifier if
two choose the same side
Inter-team Debate
• After intra-team debate, every team may
find a better combined algorithm.
• 3 teams form a group. Each team stays
together and plays now against 2 other
teams of 3 students.
• Every team will have a debate with two
other teams in the group. Team plays by
consensus against other teams.
Count losses
• Nobody drops out but we count losses in
non-forced position, first individually then
per team.
• When a team loses, loss is added to all
team members.
Time
• Debate could be going on Piazza or in
class.
• In class:
- each intra-team debate: 10min
- each inter-team debate: 12min
• Piazza:
- each intra-team debate: 720min
- each inter-team debate: 720min
Translating debates into grades
• Intra-team
– Max. 2 losses in non-forced position
• Inter-team
– Max. 2 losses in non-forced position
• Total:
–
–
–
–
–
0 losses: A
1 loss: A2 losses: B
3 losses: C+
4 losses: C
• Remember: It is possible that all three team
members get an A.
Debates Organization
• 27 students: S1 … S27
• 9 teams: T1 … T9 of 3 students each
• Intra-team: choose sides
– For i from 1 to 9
• Ti consists of S3*i, S3*i-1, S3*i-2
• 1. round: S3*i-2 – S3*i-1
• 2. round: S3*i-2 – S3*i
• 3. round: S3*i-1 – S3*I
– For each player: show number of losses in
non-forced side.
Inter-team
• Choose sides (now as a team)
– For j from 1 to 3
• 1.round: T3*j-2 – T3*j-1
• 2.round: T3*j-2 – T3*j
• 3. round: T3*j-1 – T3*j
– For each team: show number of losses in nonforced side.
After each round
• Choose one game (debate) to show to
the class.
• Choose a debate where ideally one of
the players has 0 losses in non-forced side.