| ⊦ b < a ∧ ¬ b ∈ s → #(s ++ a ++ b) = #(s ++ a) + 1 |
⊦ ¬ a ∈ s → #(s ++ a) = # s + 1
Used simplifier rules: eq: ⊦ a ∈ s → s ++ a = s; from specification set-basic%eq: ⊦ m = m + n ↔ n = 0; from specification nat-basic2%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic2%c: ⊦ m + n = n + m; from specification nat-basic2%in-03: ⊦ ¬ a ∈ s → (a ∈ s ++ b ↔ a = b); from specification set-basic%lel: ⊦ a < b ∧ a = c → c < b; (forward) from specification oelem%irreflexivity: ⊦ ¬ a < a; from specification oelem Used terms: b, s ++ a