Goal:
  
  z : t
  hd : A.t
  tl : t
  tl' : t
  H : lt_ tl tl'
  IHlt_ : forall z : t, lt tl' z -> lt tl z
  hd0 : A.t
  tl0 : t
  tl'0 : t
  H' : lt_ tl0 tl'0
  ============================
   ({| pr1 := hd :: tl'; pr2 := z |} =
    {| pr1 := hd0 :: tl0; pr2 := hd0 :: tl'0 |} ->
    let H := CoreTactics.block in
    let H0 := CoreTactics.block in lt (hd :: tl) z)


DEBUG:Going to execute:
simplify * || simplify ?