reserve G,G1,G2 for _Graph;
reserve W,W1,W2 for Walk of G;
reserve e,x,y,z for set;
reserve v for Vertex of G;
reserve n,m for Element of NAT;

theorem
  for m,n,o being odd Element of NAT st m <= n & n <= o & o <= len W
  holds W.cut(m,n).append(W.cut(n,o)) = W.cut(m,o) by Lm17;
