Multivariate Analysis of Scheduling Fair Competitions

TL;DR

This paper studies the complexity of scheduling fair competitions where each contestant faces opponents with equal total initial rankings, analyzing the problem's difficulty based on various structural parameters.

Contribution

It introduces the { extsc{Fair-NET}} problem, analyzing its classical and parameterized complexity in the context of fair competition scheduling.

Findings

Complexity results for { extsc{Fair-NET}} under various parameters.

Identification of tractable and intractable cases.

Framework for designing fair competition schedules.

Abstract

A \emph{fair competition}, based on the concept of envy-freeness, is a non-eliminating competition where each contestant (team or individual player) may not play against all other contestants, but the total difficulty for each contestant is the same: the sum of the initial rankings of the opponents for each contestant is the same. Similar to other non-eliminating competitions like the Round-robin competition or the Swiss-system competition, the winner of the fair competition is the contestant who wins the most games. The {\sc Fair Non-Eliminating Tournament} ({\sc Fair-NET}) problem can be used to schedule fair competitions whose infrastructure is known. In the {\sc Fair-NET} problem, we are given an infrastructure of a tournament represented by a graph $G$ and the initial rankings of the contestants represented by a multiset of integers $S$. The objective is to decide whether $G$ is \emph{$S$-fair}, i.e., there exists an assignment of the contestants to the vertices of $G$ such that the sum of the rankings of the neighbors of each contestant in $G$ is the same constant $k\in\mathbb{N}$. We initiate a study of the classical and parameterized complexity of {\sc Fair-NET} with respect to several central structural parameters motivated by real world scenarios, thereby presenting a comprehensive picture of it.