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graphs and networks - GraphUnion but with multiple edges?


I have two graphs G1 and G2 with the same vertex set. I would like to take the union of G1 and G2 in such a way that if both G1 and G2 contain the same edge, then the union inherits both of those edges, labeled appropriately. Unfortunately, GraphUnion[G1, G2] seems to lump common edges into one. How can I accomplish my goal?




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