Label the edges arbitrarily as e 1, . . . . ,e m with the property that em-n+1 ,..., em belong
to T. Let 6 be the minimum difference between any two non-equal edge weights; subtract
6i/n3 from the weight of edge i. Note that all edge weights are now distinct, and the sorted
order of the new weights is the same as some valid ordering of the original weights. Over all
Spanning trees of G, T is the one whose total weight has been reduced by the most; thus, it
is now the unique minimum spanning tree of G and will be returned by Kruskal’s algorithm
on this valid ordering.