rcases hf with hf | hf
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 :
  some (unit (i, b)) ∈ f.clauses.data ∨
    (∃ a,
        (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = unit (i, b)) ∨
      ∃ a,
        (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = unit (i, b)
⊢ (some (unit (i, b)) ∈ f.clauses.data ∨ unit (i, b) = c) ∨
    (∃ a,
        (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = unit (i, b)) ∨
      ∃ a,
        (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = unit (i, b)
case h_1.inl
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 : some (unit (i, b)) ∈ f.clauses.data
⊢ (some (unit (i, b)) ∈ f.clauses.data ∨ unit (i, b) = c) ∨
    (∃ a,
        (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = unit (i, b)) ∨
      ∃ a,
        (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = unit (i, b)

case h_1.inr
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 :
  (∃ a,
      (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = unit (i, b) ∨
        (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = unit (i, b)) ∨
    ∃ a,
      (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = unit (i, b) ∨
        (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = unit (i, b)
⊢ (some (unit (i, b)) ∈ f.clauses.data ∨ unit (i, b) = c) ∨
    (∃ a,
        (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = unit (i, b)) ∨
      ∃ a,
        (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = unit (i, b) ∨
          (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = unit (i, b)