exact deleteOne_preserves_assignments_size f id
n : Nat
f : DefaultFormula n
id : Nat
hsize : f.assignments.size = n
hf : ∀ (i : PosFin n) (b : Bool), hasAssignment b f.assignments[i.val] = true → unit (i, b) ∈ f.toList
⊢ (f.deleteOne id).assignments.size = f.assignments.size
no goals