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