The name of the course is combinatorics, at undergraduate level. Please provide your own expert answer, thank you!

4. (15 points) Given positive integers m, n, p, define the a graph Gm.n.p as the the graph with vertex set V = V10 V2 V3 (a disjoint union of sets V1, V2, and V3) with: Vi= {11, 12,..., Xm} V2 = {41, 42, ..., Yn} V3 = {21, 22, ..., Zp} and edge set E = E12 U E23, with: E12 = {liyj : 1 sism, 15 j<>