Title
Triangle factors of graphs without large independent sets and of weighted graphs.
Abstract
The classical Corradi-Hajnal theorem claims that every n-vertex graph G with delta(G) >= 2n/3 contains a triangle factor, when 3|n. In this paper we present two related results that both use the absorbing technique of Rodl, Rucinski and Szemeredi. Our main result determines the minimum degree condition necessary to guarantee a triangle factor in graphs with sublinear independence number. In particular, we show that if G is an n-vertex graph with alpha(G) = o(n) and delta(G) >= (1/2 + o(1)) n, then G has a triangle factor and this is asymptotically best possible. Furthermore, it is shown for every r that if every linear size vertex set of a graph G spans quadratically many edges, and delta(G) >= (1/2 + o(1)) n, then G has a K-r -factor for n sufficiently large. We also propose many related open problems whose solutions could show a relationship with Ramsey-Turan theory. Additionally, we also consider a fractional variant of the Corradi-Hajnal Theorem, settling a conjecture of Balogh-Kemkes-Lee-Young. Let t is an element of(0, 1) and w : E(K-n) -> [0, 1]. We call a triangle t-heavy if the sum of the weights on its edges is more than 3t. We prove that if 3|n and w is such that for every vertex v the sum of w(e) over edges e incident to v is at least (1+2t/3 + o(1)) n, then there are n/3 vertex disjoint heavy triangles in G. (C) 2016Wiley Periodicals, Inc. Random Struct. Alg., 49, 669-693, 2016
Year
DOI
Venue
2016
10.1002/rsa.20670
RANDOM STRUCTURES & ALGORITHMS
Keywords
Field
DocType
extremal problems,factorization,matching,partitioning,covering and packing,probabilistic methods
Sublinear function,Discrete mathematics,Graph,Independence number,Combinatorics,Vertex (geometry),Quadratic equation,Probabilistic method,Factorization,Conjecture,Mathematics
Journal
Volume
Issue
ISSN
49.0
SP4.0
1042-9832
Citations 
PageRank 
References 
0
0.34
16
Authors
3
Name
Order
Citations
PageRank
József Balogh186289.91
Theodore Molla2236.23
Maryam Sharifzadeh3113.83