fact: Definition dfs dfs1 dfs (roots : {set V}) e := if [pick x in roots] isn't Some x then (infty, e) else let: (n1, e1) := if num e x <= infty then (num e x, e) else dfs1 x e in let: (n2, e2) := dfs (roots :\ x) e1 in (minn n1 n2, e2).
imports: mathcomp(all_ssreflect) extra_nocolors