i + i = j0 ∨ i + i + 1 = j0 ⊦ ∃ i0. (i0 + i0) + 1 = j0 ∨ (i0 + i0 + 1) + 1 = j0
Used simplifier rules: succ-01: ⊦ i +1 = i + 1;% ⊦ i = j -1 ↔ i +1 = j; (s)