reserve n,m,i,j,k for Nat,
  x,y,e,X,V,U for set,
  W,f,g for Function;
reserve p,q for FinSequence;
reserve G for Graph,
  pe,qe for FinSequence of the carrier' of G;
reserve v,v1,v2,v3 for Element of G;

theorem Th24:
  vertices pe c= vertices(pe^qe) & vertices qe c= vertices(pe^qe)
proof
  rng pe c= rng (pe^qe) & rng qe c= rng (pe^qe) by FINSEQ_1:29,30;
  hence thesis by Th19;
end;
