(0,0): Error BP5003: A postcondition might not hold on this return path.
chris2.bpl(30,5): Related location: Gate not preserved by p_gt1_lower
Execution trace:
    (0,0): this_A
(0,0): Error BP5003: A postcondition might not hold on this return path.
(0,0): Related location: Gate failure of p_gt2 not preserved by p_gt1_lower
Execution trace:
    (0,0): this_A
(0,0): Error BP5003: A postcondition might not hold on this return path.
chris2.bpl(30,5): Related location: Gate not preserved by p_gt1
Execution trace:
    (0,0): this_A
(0,0): Error BP5003: A postcondition might not hold on this return path.
(0,0): Related location: Gate failure of p_gt2 not preserved by p_gt1
Execution trace:
    (0,0): this_A

Boogie program verifier finished with 2 verified, 4 errors