Globally bounded local edge colourings of hypergraphs
نویسندگان
چکیده
We consider edge colourings of K n – the complete r-uniform hypergraph on n vertices. Our main question is: how ‘colourful’ can such a colouring be if we restrict the number of colours locally? The local restriction is formulated as follows: for a fixed hypergraph H and an integer k we call a colouring (H, k)-local, if every copy of H in the complete hypergraph K n picks up at most k different colours. We will investigate the threshold of k which guarantees that every (H, k)-local colouring must have a bounded global number of colours as n tends to infinity.
منابع مشابه
Essentially Infinite Colourings of Hypergraphs
We consider edge colourings of the complete r-uniform hypergraph K (r) n on n vertices. How many colours may such a colouring have if we restrict the number of colours locally? The local restriction is formulated as follows: for a fixed hypergraph H and an integer k we call a colouring (H, k)-local if every copy of H in the complete hypergraph K (r) n receives at most k different colours. We in...
متن کاملNon-monochromatic non-rainbow colourings of σ-hypergraphs
One of the most interesting new developments in hypergraph colourings in these last few years has been Voloshin’s notion of colourings of mixed hypergraphs. In this paper we shall study a specific instance of Voloshin’s idea: a non-monochromatic non-rainbow (NMNR) colouring of a hypergraph is a colouring of its vertices such that every edge has at least two vertices coloured with different colo...
متن کاملConstrained colouring and σ-hypergraphs
A constrained colouring or, more specifically, an (α, β)-colouring of a hypergraph H, is an assignment of colours to its vertices such that no edge of H contains less than α or more than β vertices with different colours. This notion, introduced by Bujtás and Tuza, generalises both classical hypergraph colourings and more general Voloshin colourings of hypergraphs. In fact, for r-uniform hyperg...
متن کاملOn the Number of Edges in Hypergraphs Critical with Respect to Strong Colourings
A colouring of the vertices of a hypergraph G is called strong if, for every edge A, the colours of all vertices in A are distinct. It corresponds to a colouring of the generated graph 0(G) obtained from G by replacing every edge by a clique. We estimate the minimum number of edges possible in a k-critical t-uniform hypergraph with a given number of vertices. In particular we show that, for k ≥...
متن کاملA note on the discrepancy of matrices with bounded row and column sums
A folklore result uses the Lovász local lemma to analyze the discrepancy of hypergraphs with bounded degree and edge size. We generalize this result to the context of real matrices with bounded row and column sums.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Electronic Notes in Discrete Mathematics
دوره 19 شماره
صفحات -
تاریخ انتشار 2005