Can open tournaments improve the quality of city services? The proliferation of big data makes it possible to use predictive analytics to better target services like hygiene inspections, but city governments rarely have the in-house talent needed for developing prediction algorithms. Cities could hire consultants, but a cheaper alternative is to crowdsource competence by making data public and ...

Computational Social Choice (ComSoc) is a rapidly developing field at the intersection of computer science, economics, social choice, and political science. The study of tournaments is fundamental to ComSoc and many results have been published about tournament solution sets and reasoning in tournaments [4]. Theoretical results in ComSoc tend to be worst case and tell us little about performance...

BACKGROUND Standardized assessment of sports injuries provides not only important epidemiological information, but also directions for injury prevention, and the opportunity for monitoring long-term changes in the frequency and characteristics of injury. PURPOSE Development and implementation of an easy to use injury-reporting system to analyze the incidence, circumstances and characteristics...

For digraphs D and H , a mapping f : V (D)→V (H) is a homomorphism of D to H if uv ∈ A(D) implies f(u)f(v) ∈ A(H). For a fixed digraph H , the homomorphism problem is to decide whether an input digraph D admits a homomorphism to H or not, and is denoted as HOMP(H). Digraphs are allowed to have loops, but not allowed to have parallel arcs. A natural optimization version of the homomorphism probl...

A celebrated unresolved conjecture of Erdős and Hajnal states that for every undirected graph H there exists (H) > 0 such that every undirected graph on n vertices that does not contain H as an induced subgraph contains a clique or stable set of size at least n (H). The conjecture has a directed equivalent version stating that for every tournament H there exists (H) > 0 such that every H-free n...

Evolutionary tournaments have been used as a tool for comparing strategies. For instance, in the late 1970’s, Axelrod organized tournaments to compare strategies for playing the iterated prisoner’s dilemma (PD) game. While these tournaments and later research have provided us with a better understanding of successful strategies for iterated PD, our understanding is less clear about strategies f...

This paper introduces the umodules, a generalisation of the notion of module in graph theory. The structure to be decomposed, so-called homogeneous relation, captures among other undirected graphs, tournaments, digraphs, and 2−structures. Our resulting decomposition scheme when restricted to undirected graphs generalises the well-studied modular graph decomposition, and meets the recently intro...

The mechanism by which cooperation arises within populations of selfish individuals has generated significant research within the biological, social and computer sciences. Much of this interest derives from the original research of Axelrod and Hamilton, and, in particular, the two computer tournaments that Axelrod organised in order to investigate successful strategies for playing the Iterated ...

Self-Selection and the Efficiency of Tournaments When exogenously imposed, rank-order tournaments have incentive properties but their overall efficiency is reduced by a high variance in performance (Bull, Schotter, and Weigelt 1987). However, since the efficiency of performance-related pay is attributable both to its incentive effect and to its selection effect among employees (Lazear, 2000), i...

March brings March Madness, the annual conclusion to the U.S. men’s college basketball season with two single elimination basketball tournaments showcasing the best college teams in the country. Almost as mad is the plethora of office pools across the country where the object is to pick a priori as many game winners as possible in the tournament. More generally, the object in an office pool is ...