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 being Element of NAT st W.first() = W.m holds W.remove(1,m) = W
  .cut(m, len W) by Lm32;
