j < i, 0 ≤ j, 0 < i ⊦ r -- j ' ∈ addarray(r, val, i, st)
[[CONCRETESIMPRULES : ([CSIMPFORWARD : ⊦ i ≤ j ∧ 0 ≤ i → 0 ≤ j], [CSIMPFORWARD : ⊦ i < j ∧ 0 ≤ i → 0 < j])]]