(a) Define a Bipartite Graph and Complete Bipartite Graph. (b) For a complete…

(a) Define a Bipartite Graph and Complete Bipartite Graph.
(b) For a complete bipartite graph Km,n​, derive the formula for the number of edges.
(c) Find the number of edges in K3,4​ and verify whether a graph with 7 vertices and 12 edges can be a complete bipartite graph.

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Bipartite and Complete Bipartite Graphs

(a) Definitions:
A Bipartite Graph G=(V,E) is a graph whose vertex set V can be partitioned into two disjoint sets V1​ and V2​ such that every edge connects a vertex from V1 to V2. No edge exists within the same set, making both sets independent.

A Complete Bipartite Graph Km,n​ is a bipartite graph in which every vertex of V1 (size m) is connected to every vertex of V2​ (size n).

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(b) Edge Formula Derivation:
Let ∣V1∣=m and ∣V2∣=n. Each of the mmm vertices in V1​ is adjacent to all n vertices of V2.

∣E∣=m×n

(c) Numerical Verification:
Given V=7, E=12. Possible partitions: (1,6),(2,5),(3,4).

1 × 6 = 6, 2 × 5 = 10, 3 × 4 = 12

Hence, the graph can be represented as K3,4.

Key Property & Conclusion:

A graph is bipartite iff it contains no odd cycle. Thus, bipartite graphs model relationships between two distinct sets, while Km,n​ represents maximum connectivity between them, making it highly useful in network modeling and matching problems.

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