Основні поняття
The authors study the problem of finding a maximum-cardinality set of r-cliques in an undirected graph of fixed maximum degree Δ, subject to the cliques being either vertex disjoint or edge disjoint. They provide a complete complexity classification for both the vertex-disjoint and edge-disjoint variants.
Анотація
The paper studies two related problems on clique packings in undirected graphs:
- Vertex-Disjoint Kr-Packing Problem (VDKr): Find a maximum-cardinality set of r-cliques (Krs) in the graph where the cliques are pairwise vertex disjoint.
- Edge-Disjoint Kr-Packing Problem (EDKr): Find a maximum-cardinality set of Krs in the graph where the cliques are pairwise edge disjoint.
The authors provide the following results:
- If Δ < 3r/2 - 1, then VDKr and EDKr can be solved in linear time.
- If Δ < 5r/3 - 1, then VDKr can be solved in polynomial time.
- If r ≤ 5 and Δ ≤ 2r - 2, or if r ≥ 6 and Δ < 5r/3 - 1, then EDKr can be solved in polynomial time.
- If Δ ≥ ⌈5r/3⌉ - 1, then VDKr is APX-hard.
- If r ≥ 6 and Δ ≥ ⌈5r/3⌉ - 1, then EDKr is APX-hard.
- If r = 4 and Δ > 2r - 2 = 6, then EDK4 is APX-hard.
The authors provide a complete complexity classification for both VDKr and EDKr in terms of the maximum degree Δ and the fixed clique size r.