Goal:
  
  G : t
  HI : invariants G
  HG : acyclic_no_loop G
  y_0 : V.t
  x_0 : V.t
  Vx : VSet.In x_0 (V G)
  Vy : VSet.In y_0 (V G)
  K : Z
  Hxs : lsp G x_0 y_0 = Some K
  x : V.t
  y : V.t
  kxy : Z
  pxy : SPath G (V G) x y
  Hkxy : sweight pxy = kxy
  ============================
   (Some kxy <= Some kxy)%nbar


DEBUG:Going to execute:
reflexivity
Level 0: Backtrace:

Proof is not complete.
Level 0: Backtrace:

Proof is not complete.