Goal:
  
  G : t
  invG : invariants G
  acG : acyclic_no_loop G
  x : V.t
  y : V.t
  hx : VSet.In x (V G)
  hy : VSet.In y (V G)
  nxy : Z
  hxy : (lsp G x y <= Some nxy)%nbar
  nx : Z
  eqlspx : lsp G (s G) x = Some nx
  nxpos : 0 <= nx
  eqnx : Z.of_nat (to_label (lsp G (s G) x)) = nx
  ============================
   (Nat.max (stdl x) (stdl x + dxy) = (stdl x + dxy)%nat)


DEBUG:Going to execute:
apply : max_r 
DEBUG LTAC Evaluated term: l'
DEBUG LTAC Evaluated term: l'
DEBUG LTAC Evaluated term: r
DEBUG LTAC Evaluated term: r
DEBUG LTAC Evaluated term: lsp_xx
DEBUG LTAC Evaluated term: lsp_xx
DEBUG LTAC Evaluated term: to_label_to_nat
DEBUG LTAC Evaluated term: to_label_to_nat
DEBUG LTAC Evaluated term: Nat2Z.id
DEBUG LTAC Evaluated term: Nat2Z.id
DEBUG LTAC Evaluated term: Nat.add_comm
DEBUG LTAC Evaluated term: Nat.add_comm