Core Concepts
The author explores the complexity of hedonic diversity games, providing insights into Nash and individually stable outcomes based on the number of colors and coalition sizes.
Abstract
Hedonic diversity games are studied for their computational complexity in achieving stable outcomes. The research delves into various parameters affecting tractability, such as the number of colors, coalition sizes, and agent types. New algorithms and lower bounds are designed to provide a comprehensive understanding of the problem's complexity landscape.
Previous works focused on two-color cases, but this study extends to scenarios with more than two colors. The results reveal necessary conditions for tractability in hedonic diversity games, shedding light on the computational aspects of diverse coalition formations. The analysis includes stability concepts like Nash stability and individual stability.
The research introduces a parameterized-complexity picture for computing stable outcomes in hedonic diversity games. By considering different parameters like color classes, coalition sizes, and agent types, the study offers a detailed insight into the computational challenges associated with diverse coalitional settings.
Overall, the content provides a thorough examination of hedonic diversity games from a computational perspective, highlighting key factors influencing the complexity of achieving stable outcomes.
Stats
Among others, they showed that individually and Nash-stable HDG is NP-hard even when restricted to instances with 5 and 2 colors, respectively.
For each type of coalition C ∈ C we now branch to determine whether it occurs 0, 1, or at least 2 times in the solution.
Let Π = {C1, . . . , Cℓ} be a partitioning of the agents...and all Ci’s are pairwise disjoint.
We call Π an outcome...and use Πi to denote the coalition...
It holds that τ ≤ (γσ+1)! · 2γσ+1.
Quotes
"The most prominent computational question arising from the study of hedonic diversity games targets the computation of an outcome that is stable under some well-defined notion of stability."
"Our results show that apart from two trivial cases (restricting the size and number of coalitions), a necessary condition for tractability under considered parameterizations is that the number of colors is bounded by the parameter."
"In particular, our results provide a complete understanding of exact boundaries between tractable and intractable cases for HDG for both notions of stability."
"Since there are p = Pσ x=1 γx ≤ γσ+1 possible palettes...the number of branches is upper-bounded by (n + 1)γ2·τ."
"The total running time is hence at most O(σρ≥1σρ≥12)."