Dear colleagues:
You are invited to DAS Webinar, which features Prof. José Correa, a professor in the Department of Industrial Engineering and a principal researcher in the Center for Mathematical Modeling, both at Universidad de Chile. Jose obtained a mathematical engineering degree from Universidad de Chile in 1999 and a Ph.D. in Operations Research from MIT in 2004. His research, focusing on the interplay between economics and computation, has received numerous awards, including an ACM SIGecom best paper award, an INFORMS Transportation Science and Logistics best paper award, a Tucker prize finalist, and research awards from Amazon and Google. Jose serves and has served on the editorial board of some of the leading journals of his field: Mathematical Programming B, Mathematics of Operations Research, and Operations Research. Currently, Jose serves as vice-rector for Information Technology at the University of Chile.
Abstract: Apportionment is the act of distributing the seats of a legislature among political parties (or states) in proportion to their vote shares (or populations). A famous impossibility by Balinski and Young (2001) shows that no apportionment method can be proportional up to one seat (quota) while also responding monotonically to changes in the votes (population monotonicity). Grimmett (2004) proposed to overcome this impossibility by randomizing the apportionment, which can achieve quota as well as perfect proportionality and monotonicity -- at least in terms of the expected number of seats awarded to each party. Still, the correlations between the seats awarded to different parties may exhibit bizarre non-monotonicities. When parties or voters care about joint events, such as whether a coalition of parties reaches a majority, these non-monotonicities can cause paradoxes, including incentives for strategic voting. In this paper, we propose monotonicity axioms ruling out these paradoxes, and study which of them can be satisfied jointly with Grimmett's axioms. Essentially, we require that, if a set of parties all receive more votes, the probability of those parties jointly receiving more seats should increase. Our work draws on a rich literature on unequal probability sampling in statistics (studied as dependent randomized rounding in computer science). Our main result shows that a sampling scheme due to Sampford (1967) satisfies Grimmett's axioms and a notion of higher-order correlation monotonicity.
This is joint work with Paul Gölz, Ulrike Schmidt-Kraepelin, Jamie Tucker-Foltz, Victor Verdugo
This event will take place virtually on Wednesday, September 24th, 8AM PT / 11AM ET / 5PM CET. Please find below the link to register your name and email address.
https://us06web.zoom.us/webinar/register/WN_67LDUOndQFOF3Oy8M2sFlg#/registration
After registering, you will receive a confirmation email containing a calendar link and the ZOOM link to join the meeting.
You can find more information about our webinar series in the link below and register there also.
https://connect.informs.org/das/events/webinars
We look forward to seeing you there!
Kind regards,
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Onesun Yoo
Professor
University College London
London
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