Goal:
    z : Z  z0 : Z  H : (z <= z0)%Z
  ============================
   ((z0 <= z)%Z -> Some z = Some z0)


DEBUG:Going to execute:
try (solve [ inversion H ])
DEBUG LTAC Evaluated term: H
DEBUG LTAC Evaluated term: (z <= z0)%Z
Level 2: type of H
 has value 
(z <= z0)%Z