| a0 ' + y = y0 + a1 ', a ∈ y0, a = a0 ∨ a ∈ y, a0 ∈ y0 ∨ a0 = a1, a1 = a0 ∨ a1 ∈ y ⊦ y0.first = a0 |
Used simplifier rules: c: ⊦ a + x = a ' + x; from specification list%a: ⊦ (x + y) + z = x + y + z; from specification list%c-06: ⊦ a ' + x = b ' + y ↔ a = b ∧ x = y; from specification list%Nil: ⊦ [] + x = x; from specification list%c-03: ⊦ a ' = b ' + x ↔ a = b ∧ x = []; from specification list%in-empty: ⊦ ¬ a ∈ []; from specification list%x ≠ [] ⊦ a = x.first ∧ y = x.rest ↔ x = a + y; (elim) Used terms: y0, a2, y1