Question

The partition V = V1 ∪ V2 in a bipartite graph G1 is called ________

(a) bipartition of G1

(b) 2-vertex set of G1

(c) sub bipartite graphs

(d) disjoint vertex set

I got this question in an international level competition.

I need to ask this question from Bipartite Graphs in section Graphs of Discrete Mathematics

Answer 1

Right choice is (b) 2-vertex set of G1

For explanation I would say: A graph G1(V, E) is called bipartite if its vertex set V(G) can be decomposed into two non-empty disjoint subsets V1(G1) and V2(G1) in such a way that each edge e ∈ E(G) has its one end joint in V1(G1) and other endpoint in V2(G1). The partition V = V1 ∪ V2 in a bipartite graph G1 is called bipartition of G1.