| # s0 + # s1 + 1 < #((s0 ∩ s1) ++ a), a ∈ s0, a0 ∈ s0, ∀ s0. ¬ # s0 + # s1 < #(s0 ∩ s1) ⊦ a ∈ s1 |
⊦ ¬ a ∈ s → #(s ++ a) = # s + 1
# s0 + # s1 + 1 < #(s0 ∩ s1) + 1, a0 ∈ s0, a ∈ s0, ∀ s0. ¬ # s0 + # s1 < #(s0 ∩ s1) ⊦ a ∈ s1, a ∈ s0 ∩ s1
Used simplifier rules: Intersect: ⊦ a ∈ s1 ∩ s2 ↔ a ∈ s1 ∧ a ∈ s2;%int-a: ⊦ (s ∩ s0) ∩ s1 = s ∩ s0 ∩ s1;%int-c: ⊦ s ∩ s0 = s0 ∩ s; Used terms: a, s0 ∩ s1