ugraph_union/3

Availability::- use_module(library(ugraphs)).(can be autoloaded)

NewGraph is the union of Graph1 and Graph2. Example:

?- ugraph_union([1-[2],2-[3]],[2-[4],3-[1,2,4]],L).
L = [1-[2], 2-[3,4], 3-[1,2,4]]