have hf := f_readyForRupAdd.2.2 i b hb
case h_1
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
heq✝ : c.isUnit = none
i : PosFin n
b : Bool
hb :
  hasAssignment b
      { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
            assignments := f.assignments }.assignments[i.val] =
    true
⊢ unit (i, b) ∈
    { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
        assignments := f.assignments }.toList
case h_1
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
heq✝ : c.isUnit = none
i : PosFin n
b : Bool
hb :
  hasAssignment b
      { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
            assignments := f.assignments }.assignments[i.val] =
    true
hf : unit (i, b) ∈ f.toList
⊢ unit (i, b) ∈
    { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
        assignments := f.assignments }.toList