i < 0 ⊦ path∃(str, r, r1, st[r0 -- i ', val]) ↔ path∃(str, r, r1, st)
[[CONCRETESIMPRULES : ([CSIMPNAMEDFORWARD : int-abs, , forward-le-02, ⊦ j < i ∧ i ≤ 0 → j < 0])]]