I've got a quick notation question.

Currently I'm trying to do a sum over all edges of a graph as so: $$ \sum_{i, j\ \in {E}}^{m}\frac{J_{i j}}{4}Z_{i} $$

What notation would indicate I only wanted to sum the terms over edges connected to the node $i$ ? This doesn't seem right as it has the subscript $j$, which isn't referenced at all.

$$ \sum_{i\ \in {E}}^{m}\frac{J_{i j}}{4}Z_{i} $$


1 Answer 1


$$\sum_{j: \{i,j\}\in E}\cdots$$


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