MINIMUM RANK OF THE LINE GRAPH OF CORONA C-n o K-t

The minimum rank mr(G) of a simple graph G is defined to be the smallest possible rank over all symmetric real matrices whose (i, j)-th entry (for i not equal j)is nonzero whenever {i, j} is an edge in G and is zero otherwise. The corona C-n o K-t is obtained by joining all the vertices of the complete graph K-t to each n vertex of the cycle C-n. For any t, we obtain an upper bound of zero forcing number of L(C(n)oK(t)),the line graph of C-n o K-t, and get some bounds of mr(L(C(n)oK(t))).Specially for t=1, 2, we have calculated mr(L(C(n)oK(t))) by the cut-vertex reduction method.