nLab
dagger-graph

Idea

A $†$-graph is a directed graph equipped for each pair of vertices $x,y$ with an involution ${\sigma }_{x,y}:V(x,y)\to V(y,x)$.

This is one way to think of undirected graphs.

The notion of $†$-graph is to that of dagger-category as the notion of directed graph is to the ordinary notion of category.

References

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