Abstract. This paper concerns graph spanners that approximate multipaths between pair of vertices of an undirected graphs with n vertices. Classically, a spanner H of stretch s for...
Graph homomorphism, also called H-coloring, is a natural generalization of graph coloring: There is a homomorphism from a graph G to a complete graph on k vertices if and only if ...
We give a simple proof for a theorem of Katchalski, Last, and Valtr, asserting that the maximum number of edges in a geometric graph G on n vertices with no pair of parallel edges...
We shall prove that for all 3 and > 0 there exists a sparse oriented graph of arbitrarily large order with oriented girth and such that any 1/2 + proportion of its arcs induc...
Let us denote by EX (m, n; {C4, . . . , C2t}) the family of bipartite graphs G with m and n vertices in its classes that contain no cycles of length less than or equal to 2t and h...