Let G = (V, E) be a connected graph in which each edge (u, v) 
E has an associated cost C(u, v).
A Spanning Tree for G is a subgraph of G that it is a free tree connecting all vertices in V. The cost of a spanning tree is the sum of costs on its edges.
Minimum Spanning Tree
An MST of G is a spanning tree of G having a minimum cost.
