split
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
⊢ (match c.isUnit with
    | none =>
      { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
        assignments := f.assignments }
    | some (l, true) =>
      { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
        assignments := f.assignments.modify l.val addPosAssignment }
    | some (l, false) =>
      { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
        assignments := f.assignments.modify l.val addNegAssignment }).readyForRupAdd
case h_1
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
heq✝ : c.isUnit = none
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments }.readyForRupAdd

case h_2
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l✝ : PosFin n
heq✝ : c.isUnit = some (l✝, true)
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments.modify l✝.val addPosAssignment }.readyForRupAdd

case h_3
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l✝ : PosFin n
heq✝ : c.isUnit = some (l✝, false)
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments.modify l✝.val addNegAssignment }.readyForRupAdd