| ∀ a. a ∈ list2set(x0) ↔ a ∈ x0 ⊦ a0 ∈ x0, a0 = a ∨ a0 ∈ list2set(x0) ↔ a0 = a ∨ a0 ∈ x0 |
a0 ∈ list2set(x0), ∀ a. a ∈ list2set(x0) ↔ a ∈ x0 ⊦ list2set(x0) = ∅, a0 = a, # list2set(x0) = 0, a0 ∈ x0
Used simplifier rules: ⊦ s ≠ ∅ → # s ≠ 0; (forward)% ⊦ a ∈ s → s ≠ ∅; (forward)