SWI-Prolog -- add

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

Unify NewGraph with a new graph obtained by adding the list of Vertices to Graph. Example:

?- add_vertices([1-[3,5],2-[]], [0,1,2,9], NG).
NG = [0-[], 1-[3,5], 2-[], 9-[]]