| a0 ∈ x0, ∀ a. rmdup(x0) -1l a = rmdup(x0 -l a) ⊦ a = a0, rmdup(x0) -1l a = (a0 ∈ x0 -l a ⊃ rmdup(x0 -l a);a0 ' + rmdup(x0 -l a)) |
a0 ∈ x0, ∀ a. rmdup(x0) -1l a = rmdup(x0 -l a) ⊦ a = a0, rmdup(x0) -1l a = rmdup(x0 -l a)
Used simplifier rules: in-del-new: ⊦ a ∈ x -l b ↔ a ∈ x ∧ a ≠ b;