# Category Archives: Seminars

# Two CMSS seminars: Nina Anchugina & Arkadii Slinko

Speaker: Nina Anchugina & Arkadii Slinko

Affiliation: The University of Auckland

Title: Two talks see titles below

Date: Thursday, 7 May 2015

Time: 5:00 pm

Location: Room 260-325, Owen Glenn Building

1. Speaker: Nina Anchugina.

Title: A simple framework for the axiomatization of exponential and quasi-hyperbolic discounting

Time: 30 min.

Abstract: The main goal of this talk is to investigate which normative requirements, or axioms, lead to exponential and quasi-hyperbolic forms of discounting in inter-temporal decision-making. Exponential discounting has a well-established axiomatic foundation originally developed by Koopmans (1960) with subsequent contributions by several other authors. Hayashi (2003) and Olea and Strzalecki (2014) axiomatize quasi-hyperbolic discounting. In this talk we provide an alternative foundation for exponential and quasi-hyperbolic discounting, with simple, transparent axioms and relatively straightforward proofs. Using techniques by Fishburn (1982) and Harvey (1986), we show that Anscombe and Aumann’s (1963) version of Subjective Expected Utility (SEU) theory can be readily adapted to axiomatize the aforementioned types of discounting, in both finite and infinite horizon settings.

This is a joint work with Matthew Ryan.

2. Speaker: Arkadii Slinko

Title: Condorcet Domains and Median Graphs

Time 30 min

Abstract: A set of linear orders D is called a Condorcet domain if every profile composed from preferences from D has acyclic majority relation. Maximal Condorcet domains have been a subject of intense investigation, especially by Fishburn and Monjardet. Demange (2012) generalized the classical single-crossing property to the intermediate property on median graphs and proved that for every intermediate profile R with an odd number of voters on a median graph G there is a representative voter whose preference order coincides with the majority relation. We complement her result with proving that the linear orders of any profile which is intermediate on a median graph form a Condorcet domain. We prove that for any median graph there exists a profile that is intermediate with respect to that graph and that one may need at least as many alternatives as vertices to construct such a profile. We provide a polynomial-time algorithm to recognise whether or not a given profile is intermediate with respect to some median graph.

This is a joint work with Adam Clearwater (The University of Auckland) and Clemens Puppe (Karlsruhe Institute of Technology, Germany).

Everyone welcome!

# Video available: Valery Pavlov – Non-transitive Games in Business

The video from the seminar “Non-transitive Games in Business” by Valery Pavlov is now available on the CMSS YouTube channel.

# CMSS Seminar: Valery Pavlov

Speaker: Valery Pavlov

Affiliation: Information Systems and Operations Management

Title: Non-transitive games in business

Date: Tuesday, 24 Mar 2015

Time: 5:00 pm

Location: Owen Glen building, room 260-321

This paper studies a model of competition between two players who are concerned not only with their expected profits but also with their chance of earning more than the other player. As a result, the game has some similarities with the well-known Rock-Paper-Scissors game. We conduct an experiment that tests (i) the hypothesis that such competition may arise without monetary rewards, purely as a result of intrinsic competitiveness and (ii) whether such social preferences can be easily mitigated. The experimental data provide strong evidence of the intrinsic competitiveness hypothesis and indicate some possibilities for its mitigation.

We hope this study may be of interest for practicing managers. First, it broadly captures a number of common situations in which “popular” decisions clash with “good” ones. Popular decisions bring pleasing results more often than good decisions but the difference in such is not that big whereas when outcomes of good decisions result in much higher gains albeit less often. Second, the competition mechanism we analyzed may explain why employees may be reluctant to share their own decisions and when decisions of the best employees are shared with the rest the overall performance of the company may be driven away from the optimum.

Everyone welcome!

# Nimrod Talmon & Piotr Faliszewski – seminar videos now online

The CMSS was fortunate to have visitors Nimrod Talmon & Piotr Faliszewski present seminars over the last few days. Recordings from both seminars are now available on the CMSS YouTube channel.

# Seminar: 2015-03-03 P. Faliszewski

# Seminar: 2015-02-24 N.Talmon

# Seminar 2015-01-16 K. Sorokin

Speaker: Konstantin Sorokin

Affiliation: Higher School of Economics (Moscow)

Title: Candidate utility invariance under stochastic voting

Date: Friday, 16 Jan 2015

Time: 3:00 pm

Location: Room 412, Science Centre (303)

Previous work by the authors (Zakharov, 2012, Sorokin and Zakharov, 2014) demonstrated

that the shape of the functions that translate vote shares into payoffs does have an effect on

the equilibrium actions of candidates in two-candidate voting games with a finite number of

stochastic voters. In particular, we have shown that the „mean voter theorem‰ that predicts

candidates choosing identical policy positions in fact holds only for a small set of candidate

utility functions (a set that includes both winner-take-all and proportional utility).

In this work, we take our research one step further. First, we show that, as the number of

voters becomes large, the outcome of an electoral competition game is invariant with respect

to the candidate utility functions. Second, we show that this invariance holds only if the votes

are cast independently. If there is, say, a common shock to the utilities that all voters receive, then candidate payoffs will affect the equilibrium even in the limiting games when the number of voters is infinite.

Everyone welcome!

# COMPASS Seminar: M. Wilson/V. Pavlov

Title:

Overview of the Centre for Mathematical Social Sciences

Speaker:

Mark Wilson, Computer Science and Centre for Mathematical Social Sciences (accompanied by Valery Pavlov)

Abstract:

The Centre for Mathematical Social Sciences at the University of Auckland is sometimes confused with COMPASS by outsiders. Although our structure, research methods and levels of funding have been quite different, it does seem that more collaboration could be explored.

I will give a quick overview of CMSS and discuss a few current research projects.

Date, Time, Venue: Friday September 12, 1-2, COMPASS meeting room (second floor, Fale Pacifika building)

# Seminar: 2014-08-27 N. Anchugina

Speaker: Nina Anchugina

Affiliation: PhD student, Department of Mathematics

Title: Evaluating Long-Term Investment Projects: What Should The Discounting Method Be?

Date: Wednesday, 27 Aug 2014

Time: 4:00 pm

Location: CAG17/114-G17 (Commerce A)

Increasingly today there is a necessity to evaluate projects, policies and activities, whose consequences will be spread over a long period of time.

Projects are usually analysed by converting the future values into present values by attaching some weight to each period; this procedure is known as discounting. Several methods of discounting have been developed but a universal one does not exist. The choice of discounting method, however, may be vital for deciding whether a certain project should be implemented or not. The question is: Which method of discounting should be used when evaluating long-term public projects?

In this talk we will firstly consider two main types of discounting, namely exponential and hyperbolic discounting, their functional forms, properties and implications. I will provide an example which illustrates how the choice of discounting method appears to be crucial for making a decision. Secondly, we will analyse an appropriate social discount function for a public project implied by an aggregation of the individual discount functions. Finally, we will investigate the situation when there is an uncertainty about discount rates for exponential discounting, which is a common case for long-term projects. I will also present some new results on the choice of a discount rate of the hyperbolic discounting when there is uncertainty about future rates .