An induced subgraph game is a transferable utility game represented by a weighted undirected graph with one vertex per player; a coalition's value is the sum of the edge weights in its induced subgraph. With no self-loops,
where each unordered pair is counted once and an absent edge has weight zero. Weights may have either sign. In an induced subgraph game with self-loops, write the loop weight at as and add , counting each loop once. In particular, when loops are allowed and is zero otherwise.[ref]