4 research outputs found
Manipulating Tournaments in Cup and Round Robin Competitions
In sports competitions, teams can manipulate the result by, for instance,
throwing games. We show that we can decide how to manipulate round robin and
cup competitions, two of the most popular types of sporting competitions in
polynomial time. In addition, we show that finding the minimal number of games
that need to be thrown to manipulate the result can also be determined in
polynomial time. Finally, we show that there are several different variations
of standard cup competitions where manipulation remains polynomial.Comment: Proceedings of Algorithmic Decision Theory, First International
Conference, ADT 2009, Venice, Italy, October 20-23, 200
A paradox of tournament seeding
A mathematical model of seeding is analysed for sports tournaments where the
qualification is based on round-robin contests. The conditions of
strategyproofness are found to be quite restrictive: if each team takes its own
coefficient (a measure of its past performance), only one or all of them should
qualify from every round-robin contest. Thus the standard draw system creates
incentives for tanking in order to be assigned to a stronger pot as each team
prefers to qualify with teams having a lower coefficient. Major soccer
competitions are shown to suffer from this weakness. Strategyproofness can be
guaranteed by giving to each team the highest coefficient of all teams that are
ranked lower in its round-robin contest. The proposal is illustrated by the
2020/21 UEFA Champions League.Comment: 23 pages, 3 table
Can strategizing in round-robin subtournaments be avoided?
This paper develops a mathematical model of strategic manipulation in complex sports competition formats such as the soccer world cup or the Olympic games. Strategic manipulation refers here to the possibility that a team may lose a match on purpose in order to increase its prospects of winning the competition. In particular, the paper looks at round-robin tournaments where both first- and second-ranked players proceed to the next round. This standard format used in many sports gives rise to the possibility of strategic manipulation, as exhibited recently in the 2012 Olympic games. An impossibility theorem is proved which demonstrates that under a number of reasonable side-constraints, strategy-proofness is impossible to obtain