Knockout tournament design : a computational approach

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Abstract/Contents

Abstract
Knockout tournaments constitute a very common and important form of social institution. They are perhaps best known in sporting competitions, but also play a key role in other social and commercial settings as they model a specific type of election scheme (namely, sequential pairwise elimination election). In such tournaments the organizer controls the shape of the tournament (a binary tree) and the seeding of the players (their assignment to the tree leaves). A tournament can involve millions of people and billions of dollars, and yet there is no consensus on how it should be organized. It is usually dependent on arbitrary decisions of the organizers, and it remains unclear why one design receives precedence over another. The question turns out to be surprisingly subtle. It depends among other things on (a) the objective, (b) the model of the players, (c) the constraints on the structure of the tournament, and (d) whether one considers only ordinal solutions or also cardinal ones. We investigate the problem of finding a good or optimal tournament design across various settings. We first focus on the problem of tournament schedule control, i.e., designing a tournament that maximizes the winning probability of a target player. While the complexity of the general problem is still unknown, various constraints -- all naturally occurring in practice -- serve to push the problem to one side or the other: easy (polynomial) or hard (NP-complete). We then address the question of how to find a fair tournament. We consider two alternative fairness criteria, adapted from the literature: envy-freeness and order preservation. For each setting, we provide either impossibility results or algorithms (either exact or heuristic) to find such a fair tournament. We show through experiments that our heuristics are both efficient and effective. Finally, using a combination of analytic and experimental tools we investigate the optimality of ordinal solutions for three objective functions: maximizing the predictive power, maximizing the expected value of the winner, and maximizing the revenue of the tournament. The analysis relies on innovative upper bounds that allow us to evaluate the optimality of any seeding, even when the number of possible seedings is extremely large.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2010
Issuance monographic
Language English

Creators/Contributors

Associated with Vu, Thuc Duy
Associated with Stanford University, Computer Science Department.
Primary advisor Shoham, Yoav
Thesis advisor Shoham, Yoav
Thesis advisor Jackson, Matthew O
Thesis advisor Roughgarden, Tim
Advisor Jackson, Matthew O
Advisor Roughgarden, Tim

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Thuc D. Vu.
Note Submitted to the Department of Computer Science.
Thesis Ph.D. Stanford University 2010
Location electronic resource

Access conditions

Copyright
© 2010 by Thuc Duy Vu
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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