On the strength of connectedness of a random graph

If G is an arbitrary non-complete graph, let cZ1(G) denote the least number k such that by deleting k appropriately chosen vertices from G (i. e. deleting the k points in question and all edges starting from these points) the resulting graph is not connected. If G is a complete graph of order n, we put c,(G) = n-l. Let cY(G) denote the least number 1 such that by deleting 1 appropriately chosen edges from G the resulting graph is not connected. We may measure the strength of connectedness of G by any of the numbers c],(G), c$,(G) and in a certain sense {if G is known to be connected) also by c(G). Evidently one has