in citp in tree select #CITP# . loop init . ---> nocycle(mktree(G)) = true ---> Induction base (goal GRAPH |- eq nocycle(mktree(nil)) = true ;) (red) ---> Induction step fmod TH3 is ---> fth TH3 pr GRAPH . op g : -> Graph . var A : Vertex . var G : Graph . eq mcc(A,mktree(G)) = mcc(A,G) [metadata "1"] . eq nomcc(mktree(G)) = nomcc(G) [metadata "2"]. eq nocycle(mktree(g)) = true [metadata "3"]. endfm select #CITP# . loop init . (goal TH3 |- eq nocycle(mktree(< A:Vertex,B:Vertex > ; g)) = true ;) (tc red ca red)