| ⊦ (sdt[str0, tree] -- str)[str] = (sdt -- str)[str], str = str0 |
⊦ ¬ str ∈ sdt → sdt[str] = (∅)[str]
⊦ (∅)[str] = (sdt -- str)[str], str = str0, str ∈ sdt[str0, tree] -- str
Used simplifier rules: ⊦ str ∈ sdt -- str0 ↔ str ≠ str0 ∧ str ∈ sdt; (ws) Used terms: str, sdt[str0, tree] -- str