spec:
inst:
name: Subset
seq: ⊦ s1 ⊆ s2 ↔ (∀ a. a ∈ s1 → a ∈ s2)
subst: [s2, s1] → [s ++ a ++ b ++ c, s]
flags: rewrite, current
Additional information
Used simplifier rules:
add: ⊦ ¬ a ∈ s ++ b ↔ a ≠ b ∧ ¬ a ∈ s;%rax: ⊦ a ∈ s ++ b ↔ ¬ ¬(a = b ∨ a ∈ s);%in: ⊦ a ∈ s → a ∈ s ++ b;
Used terms: s ++ a ++ b ++ c, s