Abstract
We say that a graph G has a perfect H-packing if there exists a set of vertex-disjoint
copies of H which cover all the vertices in G. The seminal Hajnal–Szemer´edi theorem [12] characterises the minimum degree that ensures a graph G contains a perfect Kr-packing. Balogh,
Kostochka and Treglown [4] proposed a degree sequence version of the Hajnal–Szemer´edi theorem which, if true, gives a strengthening of the Hajnal–Szemer´edi theorem. In this paper we prove this conjecture asymptotically. Another fundamental result in the area is the Alon–Yuster theorem [3] which gives a minimum degree condition that ensures a graph contains a perfect H-packing for an arbitrary graph H. We give a wide-reaching generalisation of this result by answering another conjecture of Balogh, Kostochka and Treglown [4] on the degree sequence of a graph that forces a perfect H-packing. We also prove a degree sequence result concerning perfect transitive tournament packings in directed graphs. The proofs blend together the regularity and absorbing methods.
copies of H which cover all the vertices in G. The seminal Hajnal–Szemer´edi theorem [12] characterises the minimum degree that ensures a graph G contains a perfect Kr-packing. Balogh,
Kostochka and Treglown [4] proposed a degree sequence version of the Hajnal–Szemer´edi theorem which, if true, gives a strengthening of the Hajnal–Szemer´edi theorem. In this paper we prove this conjecture asymptotically. Another fundamental result in the area is the Alon–Yuster theorem [3] which gives a minimum degree condition that ensures a graph contains a perfect H-packing for an arbitrary graph H. We give a wide-reaching generalisation of this result by answering another conjecture of Balogh, Kostochka and Treglown [4] on the degree sequence of a graph that forces a perfect H-packing. We also prove a degree sequence result concerning perfect transitive tournament packings in directed graphs. The proofs blend together the regularity and absorbing methods.
Original language | English |
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Pages (from-to) | 13-41 |
Number of pages | 31 |
Journal | Journal of Combinatorial Theory. Series B |
Volume | 118 |
Early online date | 28 Jan 2016 |
DOIs | |
Publication status | Published - May 2016 |
Keywords
- Perfect packing
- Absorbing method
- Regularity method