Applications of balance equations to vertex switching reconstruction

Abstract

A graph is called s-vertex switching reconstructible (s-VSR) if it is uniquely defined, up to isomorphism, by the multiset of unlabeled graphs obtained by switching of all its s-vertex subsets. We show that a graph with n vertices is n/2-VSR if n = 0(mod 4), (n - 2)/2-VSR and n/2-VSR if n = 2(mod 4), (n - 1)/2-VSR if n = 1 (mod 2). For hypothetical nonreconstructible graphs, we give bounds on the number of edges (for any s) and on the maximum and minimum degree (for s = 2). We also show that for n > 9 the degree sequence is 2-VSR.