Large induced subgraphs with equated maximum degree

Large induced subgraphs with equated maximum degree

For a graph G, denote by fk(G) the smallest number of vertices that must be deleted from G so that the remaining induced subgraph has its maximum degree shared by at least k vertices. It is not difficult to prove that there are graphs for which already f2(G) ≥ √ n(1− o(1)), where n is the number of vertices of G. It is conjectured that fk(G) = Θ( √ n) for every fixed k. We prove this for k = 2,...

Sizes of graphs with induced subgraphs of large maximum degree

Graphs with n + k vertices in which every set of n +j vertices induce a subgraph of maximum degree at least n are considered. For j = 1 and for k fairly small compared to n, we determine the minimum number of edges in such graphs. In investigating the size Ramsey number of a star KI,, versus a triangle K3, Erdiis [ 1,2] conjectured that for n 3 3 any graph with no more than (2”:‘) (‘;) 1 edges ...

Disjoint subgraphs of large maximum degree

Odd induced subgraphs in graphs of maximum degree three

A long-standing conjecture asserts the existence of a positive constant c such that every simple graph of order n without isolated vertices contains an induced subgraph of order at least cn such that all degrees in this induced subgraph are odd. Radcliffe and Scott have proved the conjecture for trees, essentially with the constant c = 2/3. Scott proved a bound for c depending on the chromatic ...

Approximating Bounded Degree Maximum Spanning Subgraphs∗

The bounded degree maximum spanning subgraph problem arising from wireless mesh networks is studied here. Given a connected graph G and a positive integer d ≥ 2, the problem aims to find a maximum spanning subgraph H of G with the constraint: for every vertex v of G, the degree of v in H, dH(v), is less than or equal to d. Here, a spanning subgraph is a connected subgraph which contains all the...