| ∀ a. rmdup(x0) -1l a = rmdup(x0 -l a) ⊦ a = a0, rmdup(a0 ' + x0) -1l a = rmdup(a0 ' + (x0 -l a)) |
⊦ rmdup(a ' + x) = (a ∈ x ⊃ rmdup(x);a ' + rmdup(x))
∀ a. rmdup(x0) -1l a = rmdup(x0 -l a) ⊦ a = a0, (a0 ∈ x0 ⊃ rmdup(x0);a0 ' + rmdup(x0)) -1l a = rmdup(a0 ' + (x0 -l a))
Used terms: x0, a0