Abstract: | Let X = (V, E) be a connected graph. Call X super restricted edge connected in short, sup-λ′, if F is a minimum edge set of X such that X − F is disconnected and every component of X − F has at least two vertices, then F is the set of edges adjacent to a certain edge with minimum edge degree in X. A bipartite graph is said to be half vertex transitive if its automorphism group is transitive on the sets of its bipartition.
In this article, we show that every connected half vertex transitive graph X with n = |V(X)| ≥ 4 and
X \ncong K1,n-1{X \ncong K_{1,n-1}} is λ′-optimal. By studying the λ′-superatoms of X, we characterize sup-λ′ connected half vertex transitive graphs. As a corollary, sup-λ′ connected Bi-Cayley graphs are also
characterized. |