fact: Definition kosaraju := let f := pdfs (rgraph [rel x y | r y x]) in (foldl (fun (p : {set T} * seq (seq T)) x => if x \notin p.1 then p else let p1 := f (p.1, [::]) x in (p1.1, p1.2 :: p.2)) (setT, [::]) (tseq (rgraph r))).2.
imports: mathcomp(all_ssreflect) extra