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
  k : Z
  Hk : lsp G x_0 x = Some k
  y0x0 : Z
  w : - K <= y0x0
  ============================
   ((lsp G x_0 x <= lsp G' x_0 x)%nbar ->
    (Some (- K + k)%Z <= Some y0x0 + lsp G' x_0 x)%nbar)


DEBUG:Going to execute:
<coq-core.plugins.ssreflect::ssrrewrite@0> $1 $2
DEBUG LTAC Evaluated term: (lsp_codistance G' y_0 x_0 x)
DEBUG LTAC Evaluated term: lsp_G'_yx
DEBUG LTAC Evaluated term: le_Some_lsp
DEBUG LTAC Evaluated term: (lsp_G'_incr x_0 x)