Invites you to a

Microeconomics Theory seminar presented by

Yves Sprumont

(Deakin University)

Randomized collective choices based on a weighted tournament

18 April 2023
4.00pm – 5.00pm

Via Zoom: 835 3623 1213

Abstract: ’A rational weighted tournament x specifies for every pair of social alternatives i,j the proportion x_{ij} of voters (with linear preference orderings) who prefer i to j. An extension rule assigns to each x a random choice function y (specifying a collective choice probability distribution for each subset of alternatives) that chooses i from {i,j} with probability x_{ij}.

We analyze extension rules axiomatically. We impose that the random choice function y be stochastically rational. We show that there exist multiple neutral and stochastically rational extension rules. Linearity (requiring that y be a linear function of x) and Independence of Irrelevant Comparisons (asking that the probability distribution on a subset of alternatives depend only on the restriction of the weighted tournament to that subset) are incompatible with very weak properties implied by stochastic rationality.

We identify a class of domains, which we call sequentially binary, guaranteeing that a weighted tournament arising from a population of voters with preferences in such a domain has a unique stochastically rational extension.

For further information contact: Microeconomics Theory seminar series coordinators Dr Mengke Wang (mengke.wang@sydney.edu.au) & Dr Mert Kimya (mert.kimya@sydney.edu.au)

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