| ∀ y. rmdup(x0 + rmdup(y)) = rmdup(x0 + y), a ∈ x0 ∨ a ∈ y ⊦ rmdup(x0 + rmdup(y)) = rmdup((a ' + x0) + y) |
a ∈ rmdup(y), ∀ y. rmdup(x0 + rmdup(y)) = rmdup(x0 + y), a ∈ x0 ∨ a ∈ y ⊦ rmdup(x0 + rmdup(y)) = rmdup((a ' + x0) + y)
∀ y. rmdup(x0 + rmdup(y)) = rmdup(x0 + y), a ∈ x0 ∨ a ∈ y ⊦ a ∈ rmdup(y), rmdup(x0 + rmdup(y)) = rmdup((a ' + x0) + y)
Used formulas: a ∈ rmdup(y)