Graph Fusion
- Let
uandvbe two distinct vertices in graph G. - The fusion of the vertices u and v are treated as a single new vertex
wand every edge which was incident on u and v, are now incident onw. - After fusion,
number of vertices in the graph always decreases by one.- If original graph has
nvertices, after fusion it will haven-1vertices.
- If original graph has
- But, the number of edges may increase or decrease or remain the same.
In all the below diagrams, we fuse vertices B and C.
=> Simple graph:

=> Vertices reduced but edges remain same:

=> Fusion creating self-loop:

=> Fusion in graph with self-loop:

Credits: GeeksforGeeks