(i1 + 1) + j = (i1 + 1) + i0, ∀ j, i0. i1 + j = i1 + i0 → j = i0 ⊦ j = i0
Used simplifier rules: succ-01: ⊦ i +1 = i + 1;%add-a: ⊦ i + j + i0 = (i + j) + i0;