Consider the weighted spanning tree measure on an electric network where the probability of a spanning tree is proportional to the product of all conductances along the edges of that tree. Prove negative association for this measure, namely that if f, g are two edges (not equal) and that T is sampled according to the weighted tree measure, then P(f T, g T ) P(f T )P(g T ), i.e. P(f T | g T ) P(f T )