fact: Fixpoint n_comp_dfs_rec n (s: seq T) := if n isn't n'.+1 then 0 else if s is y::s' then let p := connect_dfs y in (n_comp_dfs_rec n' (filter [predC p] s')).+1 else 0.
imports: mathcomp(all_ssreflect) fourcolor(hypermap geometry) GraphTheory(preliminaries digraph sgraph) GraphTheory(hmap_ops embedding)