have i_in_bounds : i.1 < f.assignments.size := by rw [hf.2.1]; exact i.2.2
case intro
n : Nat
f : DefaultFormula n
hf : f.ratUnits = #[] ∧ f.assignments_invariant
c : DefaultClause n
p : PosFin n → Bool
pf : p ⊨ f
insertUnit_fold_success : (List.foldl insertUnit (f.ratUnits, f.assignments, false) c.negate).2.snd = true
i : PosFin n
hboth : (List.foldl insertUnit (f.ratUnits, f.assignments, false) c.negate).snd.fst[i.val] = both
⊢ p ⊨ c
case intro
n : Nat
f : DefaultFormula n
hf : f.ratUnits = #[] ∧ f.assignments_invariant
c : DefaultClause n
p : PosFin n → Bool
pf : p ⊨ f
insertUnit_fold_success : (List.foldl insertUnit (f.ratUnits, f.assignments, false) c.negate).2.snd = true
i : PosFin n
hboth : (List.foldl insertUnit (f.ratUnits, f.assignments, false) c.negate).snd.fst[i.val] = both
i_in_bounds : i.val < f.assignments.size
⊢ p ⊨ c