# Colon/Sipma: Practical Methods for Proving Program Termination
(VAR i j)
(RULES
eval_1(i, j) -> eval_2(i, 0) :|: i >= 0
eval_2(i, j) -> eval_2(i, j + 1) :|: j <= i - 1
eval_2(i, j) -> eval_1(i - 1, j) :|: j > i - 1
)