TY - JOUR
T1 - Covering and tiling hypergraphs with tight cycles
AU - Han, Jie
AU - Lo, Allan
AU - Sanhueza-Matamala, Nicolás
N1 - Publisher Copyright:
© 2020 The Author(s)
PY - 2021/3
Y1 - 2021/3
N2 - A k-uniform tight cycle is a hypergraph on s > k vertices with a cyclic ordering such that every k consecutive vertices under this ordering form an edge. The pair (k, s) is admissible if gcd (k, s) = 1 or k / gcd (k,s) is even. We prove that if and H is a k-uniform hypergraph with minimum codegree at least (1/2 + o(1))|V(H)|, then every vertex is covered by a copy of. The bound is asymptotically sharp if (k, s) is admissible. Our main tool allows us to arbitrarily rearrange the order in which a tight path wraps around a complete k-partite k-uniform hypergraph, which may be of independent interest. For hypergraphs F and H, a perfect F-Tiling in H is a spanning collection of vertex-disjoint copies of F. For, there are currently only a handful of known F-Tiling results when F is k-uniform but not k-partite. If s 0 mod k, then is not k-partite. Here we prove an F-Tiling result for a family of non-k-partite k-uniform hypergraphs F. Namely, for, every k-uniform hypergraph H with minimum codegree at least (1/2 + 1/(2s) + o(1))|V(H)| has a perfect-Tiling. Moreover, the bound is asymptotically sharp if k is even and (k, s) is admissible.
AB - A k-uniform tight cycle is a hypergraph on s > k vertices with a cyclic ordering such that every k consecutive vertices under this ordering form an edge. The pair (k, s) is admissible if gcd (k, s) = 1 or k / gcd (k,s) is even. We prove that if and H is a k-uniform hypergraph with minimum codegree at least (1/2 + o(1))|V(H)|, then every vertex is covered by a copy of. The bound is asymptotically sharp if (k, s) is admissible. Our main tool allows us to arbitrarily rearrange the order in which a tight path wraps around a complete k-partite k-uniform hypergraph, which may be of independent interest. For hypergraphs F and H, a perfect F-Tiling in H is a spanning collection of vertex-disjoint copies of F. For, there are currently only a handful of known F-Tiling results when F is k-uniform but not k-partite. If s 0 mod k, then is not k-partite. Here we prove an F-Tiling result for a family of non-k-partite k-uniform hypergraphs F. Namely, for, every k-uniform hypergraph H with minimum codegree at least (1/2 + 1/(2s) + o(1))|V(H)| has a perfect-Tiling. Moreover, the bound is asymptotically sharp if k is even and (k, s) is admissible.
UR - http://www.scopus.com/inward/record.url?scp=85094818097&partnerID=8YFLogxK
U2 - 10.1017/S0963548320000449
DO - 10.1017/S0963548320000449
M3 - Article
AN - SCOPUS:85094818097
SN - 0963-5483
VL - 30
SP - 288
EP - 329
JO - Combinatorics Probability and Computing
JF - Combinatorics Probability and Computing
IS - 2
ER -