| ∀ lref. lref ∈ q.lebrefs ↔ (∃ n. eq-entry(n, lref) ∈ q) ∧ lref ≠ none, ∃ n. eq-entry(n, lref) = eq-entry(m, lref0) ∨ eq-entry(n, lref) ∈ q ⊦ lref = none, lref ∈ q.lebrefs ∪ (lref0 ≠ none ⊃ ∅ ++ lref0;∅) |
∀ lref. lref ∈ q.lebrefs ↔ (∃ n. eq-entry(n, lref) ∈ q) ∧ lref ≠ none, eq-entry(n, lref) = eq-entry(m, lref0) ∨ eq-entry(n, lref) ∈ q ⊦ lref = none, lref ∈ q.lebrefs, lref ∈ (lref0 ≠ none ⊃ ∅ ++ lref0;∅)
Used simplifier rules: unc: ⊦ s1 ∪ s2 = s2 ∪ s1; from specification set-union[lebrefset]%una: ⊦ (s2 ∪ s3) ∪ s4 = s2 ∪ s3 ∪ s4; from specification set-union[lebrefset]% ⊦ lref ∈ s ∪ s0 ↔ lref ∈ s ∨ lref ∈ s0; (ws)