A degree sequence Hajnal-Szemerédi theorem
نویسنده
چکیده
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–Szemerédi 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–Szemerédi theorem which, if true, gives a strengthening of the Hajnal–Szemerédi 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.
منابع مشابه
A multipartite Hajnal-Szemerédi theorem
The celebrated Hajnal-Szemerédi theorem gives the precise minimum degree threshold that forces a graph to contain a perfect Kk-packing. Fischer’s conjecture states that the analogous result holds for all multipartite graphs except for those formed by a single construction. Recently, we deduced an approximate version of this conjecture from new results on perfect matchings in hypergraphs. In thi...
متن کاملTowards a Weighted Version of the Hajnal-Szemerédi Theorem
For a positive integer r ≥ 2, a Kr-factor of a graph is a collection vertex-disjoint copies of Kr which covers all the vertices of the given graph. The celebrated theorem of Hajnal and Szemerédi asserts that every graph on n vertices with minimum degree at least (1− 1r )n contains a Kr-factor. In this note, we propose investigating the relation between minimum degree and existence of perfect Kr...
متن کاملA Short Proof of the Hajnal-Szemerédi Theorem on Equitable Coloring
An equitable k-coloring of a graph G is a proper k-coloring, for which any two color classes differ in size by at most one. Equitable colorings naturally arise in some scheduling, partitioning, and load balancing problems [1, 15, 16]. Pemmaraju [13] and Janson and Ruciński [6] used equitable colorings to derive deviation bounds for sums of dependent random variables that exhibit limited depende...
متن کاملA Short Proof of the Hajnal-Szemerédi Theorem on Equitable Colouring
An equitable k-colouring of a graph G is a proper k-colouring, for which any two colour classes differ in size by at most one. Equitable colourings naturally arise in some scheduling, partitioning, and load-balancing problems [1, 15, 16]. Pemmaraju [13] and Janson and Ruciński [6] used equitable colourings to derive deviation bounds for sums of random variables that exhibit limited dependence. ...
متن کاملVariants of the Hajnal-Szemerédi Theorem
The Hajnal-Szemer edi Theorem 6] states that a graph with hk vertices and minimum degree at least (h?1)k contains k vertex disjoint copies of K h. Its proof is not algorithmic. Here, we present an algorithm which, for a xed h, nds in such a graph k?C(h) vertex disjoint copies of K h in polynomial time in k, C(h) being a constant depending on h only. The proof suggests a variant of the theorem f...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- J. Comb. Theory, Ser. B
دوره 118 شماره
صفحات -
تاریخ انتشار 2016