| ⊦ c ' + x + b ' = y + a ' + a ' + z ∧ a ≠ b → a ∈ x |
c ' + x + b ' = y + a ' + a ' + z, c ∈ y ∨ c = a ∨ c ∈ z ⊦ a = b, a ∈ x
Used simplifier rules: in-16: ⊦ x + a ' = y + b ' + z ∧ a ≠ b → a ∈ z;%a: ⊦ (x + y) + z = x + y + z;%in-14: ⊦ a ' + x = y → a ∈ y;%in-15: ⊦ x + a ' = y → a ∈ y;%in-01: ⊦ a ≠ b → (a ∈ b ' + x ↔ a ∈ x);%in-16: ⊦ x + a ' = y + b ' + z ∧ a ≠ b → a ∈ z;%in-append: ⊦ a ∈ x + y ↔ ¬ ¬(a ∈ x ∨ a ∈ y);%in-rec: ⊦ a ∈ b ' + x ↔ ¬ ¬(a = b ∨ a ∈ x);