You are an expert Lean4 and formal verification agent proving a Lean4 theorem. Your output **must** strictly adhere to the specified format.

### Input Information
You will receive the following components, relevant to the target theorem:
* <all_available_defs>: Definitions available from imported modules (either from the current Lean repository or from Mathlib)
* <all_available_lemmas>: Lemmas/theorems available that may assist the proof.
* <local_ctx>...</local_ctx>: The local file context (imports, namespaces, definitions, comments, etc.) from the top of the file up to—but not including—the target theorem or any previously defined local lemmas/theorems.
* <target_theorem>...</target_theorem>: The target theorem statement, ending with `:=`.

**Notes**
1. Definitions include their full bodies, but for definitions whose bodies contain proofs, the proof parts are replaced by `admit` (i.e., admit /- proof elided -/), while the rest of the definition is kept unchanged; lemmas include only their statements.
2. You may freely reference any definition or lemma contained in these tags without redefining them.
3. The tags for available definitions and lemmas (all_available_defs, all_available_lemmas) may be omitted if empty.

### Output Format & Requirements
Your output MUST contain a complete, syntactically correct Lean 4 proof for the target theorem.

**Strict Output Structure:**
<reasoning> 
...
</reasoning> 

<lean4_invented_lemmas>
-- each lemma is a full Lean 4 declaration with a complete proof
...
</lean4_invented_lemmas>

<lean4_proof>
-- Lean 4 proof body of the target theorem
...
</lean4_proof>

**Requirements:**
1. <reasoning> and <lean4_invented_lemmas> are OPTIONAL. Include them only if they aid proof construction.
2. <lean4_proof> MUST contain only the proof body (tactics/terms), starting by "by", NOT the theorem declaration.
3. <lean4_invented_lemmas> (if present) MUST contain syntactically correct lemma declarations that type checks AND complete proof bodies. Defining a lemma using `axiom` is NOT allowed.
4. <reasoning> contains high-level proof planning.
5. If you create a lemma under <lean4_invented_lemmas> whose name is namespaced (e.g., X.Y.Z), you MUST always refer to it using its fully qualified name. Do NOT rely on shortened names. For example, write rw [X.Y.Z], not rw [Z] for invented lemmas.
6. All Lean 4 code MUST be syntactically correct. No `sorry`, `admit`, or non-Lean text. Comments allowed using `--` or `/- ... -/`.
7. Follow the tags and structure EXACTLY. No extra text before, between, or after the sections.
8. Do NOT wrap invented lemmas in a `mutual` block unless they have genuine mutual recursion. Declare each lemma independently.

### Examples are provided here (example input are under "User Prompt", and example assistant response are under "Agent Response"):
Example 1 ------------------- 
User Prompt:
<all_available_defs>
structure BitVec (w : Nat) where
  /-- Construct a `BitVec w` from a number less than `2^w`.
  O(1), because we use `Fin` as the internal representation of a bitvector. -/
  ofFin ::

  /-- Interpret a bitvector as a number less than `2^w`.
  O(1), because we use `Fin` as the internal representation of a bitvector. -/
  toFin : Fin (hPow 2 w)
</all_available_defs>

<all_available_lemmas>
theorem List.getElem_append_left{α : Type u_1} {l₁ l₂ : List α} {i : Nat} (hn : i < l₁.length) : (l₁ ++ l₂)[i] = l₁[i]
theorem getElem_eq_testBit_toNat (x : BitVec w) (i : Nat) (h : i < w) :
  x[i] = x.toNat.testBit i := rfl
@[simp, grind =] theorem toNat_cons (b : Bool) (x : BitVec w) :
    (cons b x).toNat = (b.toNat <<< w) ||| x.toNat
@[simp, grind =] theorem getLsbD_of_ge (x : BitVec w) (i : Nat) (ge : w ≤ i) : getLsbD x i = false
theorem testBit_toNat (x : BitVec w) : x.toNat.testBit i = x.getLsbD i
</all_available_lemmas>

<local_ctx>
import Mathlib.Computability.NFA
import Mathlib.Data.FinEnum
import Mathlib.Data.Rel
import Mathlib.Data.Vector.Basic
import Blase.AutoStructs.ForLean

open Set
open Mathlib
open SetRel

-- this is better because card is defeq to n
instance (α : Type) : Inter (Language α) := ⟨Set.inter⟩
instance (α : Type) : Union (Language α) := ⟨Set.union⟩

/--
The set of `n`-tuples of bit vectors of an arbitrary width.
-/
structure BitVecs (n : Nat) where
  w : Nat
  bvs : List.Vector (BitVec w) n

def BitVecs.cast (bvs : BitVecs n) (h : n = n') : BitVecs n' :=
  { w := bvs.w, bvs := h ▸ bvs.bvs }

abbrev BitVecs.empty : BitVecs n := ⟨0, List.Vector.replicate n .nil⟩
abbrev BitVecs.singleton {w : Nat} (bv : BitVec w) : BitVecs 1 := ⟨w, bv ::ᵥ .nil⟩
abbrev BitVecs.pair {w : Nat} (bv1 bv2 : BitVec w) : BitVecs 2 := ⟨w, bv1 ::ᵥ bv2 ::ᵥ .nil⟩

/--
The set of `n`-tuples of bit vectors of an arbitrary width, encoded as a list of
bit vectors of width `n`. The width of the encoded bit vectors is the length of
the list.
-/
abbrev BitVecs' (n : Nat) := List (BitVec n)

@[simps]
def dec (bvs' : BitVecs' n) : BitVecs n where
  w := bvs'.length
  bvs := List.Vector.ofFn fun k => BitVec.ofFn fun i => bvs'[i].getLsbD k

@[simp]
</local_ctx>

<target_theorem>
lemma dec_snoc n (bvs' : BitVecs' n) (a : BitVec n) :
  dec (bvs' ++ [a]) =
    { w := bvs'.length + 1
      bvs := List.Vector.ofFn fun k =>
        BitVec.cons (a.getLsbD k) ((dec bvs').bvs.get k) } :=
</target_theorem>

Agent Response:
<reasoning> 
The goal is to understand what `dec` does after appending one more bitvector `a` to `bvs'`. By definition, `dec` builds a width `= length` and a vector of bitvectors whose `i`-th bit at position `k` is `bvs'[i].getLsbD k`. So for `bvs' ++ [a]`, we expect the width to increase by 1 and each resulting bitvector to be `BitVec.cons` of the new bit coming from `a`.

First, I use `ext` twice: once on the record to focus on the `bvs` field, and once on the resulting bitvector. This reduces everything to a pointwise statement:
for fixed `k` and `i` with `i < bvs'.length + 1`,
the bit `(bvs' ++ [a])[i].getLsbD k` should match the bit at index `i` of `BitVec.cons (a.getLsbD k) ((dec bvs').bvs.get k)`.

At this point I need a clean description of indexing into `BitVec.cons`: if we have `x : BitVec n`, then `(cons b x)[i]` should give `b` at the new “last” index `n` and `x[i]` otherwise. That motivates an auxiliary lemma `getElem_cons` expressing exactly this behavior, proved via the `testBit`/`toNat` characterization and a case split on `i < n`, `i = n`, `i > n`.

Using `getElem_cons`, the RHS becomes an `if` on whether `i = bvs'.length`. So I split into cases:
- If `i = bvs'.length`, then `(bvs' ++ [a])[i]` is the appended `a`, so both sides reduce to `a.getLsbD k`.
- If `i ≠ bvs'.length`, the bound `i < bvs'.length + 1` forces `i < bvs'.length`. Then `(bvs' ++ [a])[i] = bvs'[i]` by `List.getElem_append_left`, and the RHS takes the “else” branch and likewise gives the bit from `bvs'[i]`. In both subcases, `simp` (plus the definition of `dec`) finishes.

So the whole proof is: `ext` to bit level, unfold `dec` with `simp_all`, rewrite with `getElem_cons`, split on the boundary index `i = length bvs'`, and in the “< length” branch use `List.getElem_append_left` and bounds to line up both sides.
</reasoning> 

<lean4_invented_lemmas>
@[grind =]
theorem getElem_cons {b : Bool} {n} {x : BitVec n} {i : Nat} (h : i < n + 1) :
    (cons b x)[i] = if h : i = n then b else x[i] := by
  simp only [BitVec.getElem_eq_testBit_toNat, BitVec.toNat_cons, Nat.testBit_or]
  rw [Nat.testBit_shiftLeft]
  rcases Nat.lt_trichotomy i n with i_lt_n | i_eq_n | n_lt_i
  · have p1 : ¬(n ≤ i) := by omega
    have p2 : i ≠ n := by omega
    simp [p1, p2]
  · simp only [i_eq_n, ge_iff_le, Nat.le_refl, decide_true, Nat.sub_self, Nat.testBit_zero,
    Bool.true_and, BitVec.testBit_toNat, BitVec.getLsbD_of_ge, Bool.or_false]
    cases b <;> trivial
  · have p1 : i ≠ n := by omega
    have p2 : i - n ≠ 0 := by omega
    simp [p1, p2, Nat.testBit_bool_toNat]
</lean4_invented_lemmas>

<lean4_proof>
by
  ext k i hi <;> simp_all
  rw [getElem_cons]
  split
  next heq => simp_all
  next h =>
    have hlt : i < List.length bvs' := by simp at hi; omega
    rw [List.getElem_append_left hlt]
    simp
</lean4_proof>

### Your task:
<all_available_defs>
Fin in Init.Prelude
Polynomial in Mathlib.Algebra.Polynomial.Basic
Finset in Mathlib.Data.Finset.Defs
Finset.add in Mathlib.Algebra.Group.Pointwise.Finset.Basic
Finset.range in Mathlib.Data.Finset.Range

def liftF (f : Fin n → α) : ℕ → α :=
  fun m ↦ if h : m < n then f ⟨m, h⟩ else 0

noncomputable def errorBound (δ : ℝ≥0) (deg : ℕ) (domain : ι ↪ F) : ℝ≥0 :=
  letI ρ : ℝ≥0 := ρ (ReedSolomon.code domain deg)
  if δ ∈ Set.Ioc 0 ((1 - ρ)/2)
  then Fintype.card ι / Fintype.card F
  else if δ ∈ Set.Ioo ((1 - ρ)/2) (1 - ρ.sqrt)
       then letI m := min (1 - ρ.sqrt - δ) (ρ.sqrt / 20)
            ⟨(deg ^ 2 : ℝ≥0) / ((2 * m) ^ 7 * (Fintype.card F : ℝ)), by admit /- proof elided -/
            ⟩
       else 0

Polynomial.degree in Mathlib.Algebra.Polynomial.Degree.Definitions

embed := ⟨fun j => by admit /- proof elided -/
  ⟩
  hEq := fun oracleIdx => by admit /- proof elided -/

@[inline] def min [Zero T] [ToNat T] (a b : Cayley T) : Cayley T :=
  if (a : Nat) ≤ (b : Nat) then a else b

instance coe_field_adjoinRoot (k : ℕ) : Coe (AdjoinRoot (poly k)) (BTField (k+1)) where
  coe := Eq.mp (BTField_succ_eq_adjoinRoot k)

@[reducible]
def SimOracle.Stateless (spec : OracleSpec ι) (specₜ : OracleSpec ιₜ) :=
  QueryImpl spec (OracleComp specₜ)

instance : ∀ i, VCVCompatible ((default : ProtocolSpec 0).Challenge i) := fun ⟨i, _⟩ => Fin.elim0 i

@[reducible]
def OracleStatement (i : Fin (k + 1)) : Fin (i.val + 1) → Type :=
  fun j =>
    evalDomain D x (∑ j' ∈ finRangeTo j.1, s j')
      → F

private def Fi (B : Finset (Fin n → F)) (i : Fin n) (α : F) : Finset (Fin n → F) :=
  { x | x ∈ B ∧ x i = α }

instance : LT AssocNat where
  lt a b := a 0 < b 0

is_complete : vectorIOP.perfectCompleteness (pure ()) ⟨isEmptyElim⟩ completeRelation

instance {relIn : Set (StmtIn × WitIn)} {relOut : Set (StmtOut × WitOut)}
    {verifier : Verifier oSpec StmtIn StmtOut pSpec} {WitMid : Fin (n + 1) → Type}
    {extractor : Extractor.RoundByRound oSpec StmtIn WitIn WitOut pSpec WitMid} :
    CoeFun (verifier.KnowledgeStateFunction init impl relIn relOut extractor)
    (fun _ => (m : Fin (n + 1)) → StmtIn → Transcript m pSpec → WitMid m → Prop) :=
      ⟨fun f => f.toFun⟩

@[app_unexpander Fin.hcons]
def hconsUnexpander : Lean.PrettyPrinter.Unexpander
  | `($_ $term !h[$term2, $terms,*]) => `(!h[$term, $term2, $terms,*])
  | `($_ $term !h[$term2]) => `(!h[$term, $term2])
  | `($_ $term !h[]) => `(!h[$term])
  | _ => throw ()

Odd in Mathlib.Algebra.Ring.Parity

noncomputable def toMvPolynomialAlgEquiv : P ≃ₐ[R] MvPolynomial σ R where
  toFun := toMvPolynomialAlgHom
  invFun := ofMvPolynomialAlgHom
  left_inv p := by admit /- proof elided -/

Subgroup in Mathlib.Algebra.Group.Subgroup.Defs

def implGroupExpOracle : QueryImpl (GroupExpOracle ι p) (StateT (GroupValTable ι G) Option) where
  impl | query _ ⟨i, a, j⟩ => fun table =>
    match table i with
    | some g => some ((), table.update j (some (g ^ a.val)))
    | none => none

Polynomial.ofFinsupp in Mathlib.Algebra.Polynomial.Basic

@[reducible]
def VectorIOP
    (Statement : Type) {ιₛ : Type} (OStatement : ιₛ → Type) (Witness : Type)
    (vPSpec : ProtocolSpec.VectorSpec n) (A : Type)
    [∀ i, OracleInterface (OStatement i)] :=
  OracleProof []ₒ Statement OStatement Witness (vPSpec.toProtocolSpec A)

AdjoinRoot.instField in Mathlib.RingTheory.AdjoinRoot

WithTop in Mathlib.Order.TypeTags

HMul.hMul in Init.Prelude

def LeafData.optionComposeBuild {α : Type} {s : Skeleton} (leaf_data_tree : LeafData α s)
    (compose : α → α → Option α) :
    FullData (Option α) s :=
  (leaf_data_tree.map (.some)).composeBuild (Option.doubleBind compose)

def fiberwiseClose (i : Fin ℓ) (steps : ℕ) [NeZero steps] (h_i_add_steps : i.val + steps ≤ ℓ)
    (f : OracleFunction 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate)
      ⟨i, by admit /- proof elided -/
      ⟩) : Prop :=
  2 * fiberwiseDistance 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (i := i) steps
    (h_i_add_steps := h_i_add_steps) (f := f) < (BBF_CodeDistance ℓ 𝓡 ⟨i + steps, by admit /- proof elided -/
    ⟩ : ℕ∞)

def finalSumcheckKStateProp {m : Fin (1 + 1)} (tr : Transcript m (pSpecFinalSumcheckStep (L := L)))
    (stmt : Statement (L := L) (SumcheckBaseContext L ℓ) (Fin.last ℓ))
    (witMid : FinalSumcheckWit (L := L) 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (ℓ := ℓ) m)
    (oStmt : ∀ j, OracleStatement 𝔽q β
      (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ϑ (Fin.last ℓ) j) : Prop :=
  match m with
  | ⟨0, _⟩ => 
    masterKStateProp 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (𝓑 := 𝓑)
      (mp := BBF_SumcheckMultiplierParam)
      (stmtIdx := Fin.last ℓ) (oracleIdx := Fin.last ℓ) (h_le := le_refl _)
      (stmt := stmt) (wit := witMid) (oStmt := oStmt) (localChecks := True)
  | ⟨1, _⟩ => 
    let tr_so_far := (pSpecFinalSumcheckStep (L := L)).take 1 (by admit /- proof elided -/
    )
    let i_msg0 : tr_so_far.MessageIdx := ⟨⟨0, by admit /- proof elided -/
    ⟩, rfl⟩
    let c : L := (ProtocolSpec.Transcript.equivMessagesChallenges (k := 1)
      (pSpec := pSpecFinalSumcheckStep (L := L)) tr).1 i_msg0

instance instInvConcreteBTF {k : ℕ} : Inv (ConcreteBTField k) where
  inv := concrete_inv

def Fin.sumCommEquiv (m : ℕ) (n : ℕ) : Fin (m + n) ≃ (Fin n) ⊕ (Fin m) :=
  (@finSumFinEquiv m n).symm.trans (Equiv.sumComm (Fin m) (Fin n))

noncomputable def basisVectors (ℓ : Nat) (h_ℓ : ℓ ≤ r) :
  Fin (2 ^ ℓ) → L⦃<2^ℓ⦄[X] :=
  fun j => ⟨Xⱼ 𝔽q β ℓ h_ℓ j, by admit /- proof elided -/
  ⟩

class HListRepr (α : Type _) where
  repr: α → Std.Format

noncomputable def batchProver :
  OracleProver []ₒ
    Unit (OracleStatement D x m) (Witness F s d m)
    ((Fin m → F) × Fri.Spec.Statement F (0 : Fin (k + 1)))
      (OracleStatement D x m) (Fri.Spec.Witness F s d (0 : Fin (k + 2)))
    (batchSpec F m) where
  PrvState
  | 0 => (∀j, OracleStatement D x m j) × Witness F s d m
  | 1 => (Fin m → F) × (∀j, OracleStatement D x m j) × Fri.Spec.Witness F s d (0 : Fin (k + 2))

def degree (P : Params ι F) : Fin (M + 1) → ℕ :=
  fun i => P.deg / ∏ j < i, (P.foldingParam j)

Mul in Init.Prelude

def churchAnd (p q : ChurchBool α) : ChurchBool α :=
  fun x y => p (q x y) y

MvPolynomial.monomial in Mathlib.Algebra.MvPolynomial.Basic

Polynomial.support in Mathlib.Algebra.Polynomial.Basic

@[reducible, simp]
def OracleStatement.Lens.IsSound {OuterStmtIn OuterStmtOut InnerStmtIn InnerStmtOut : Type}
    {Outer_ιₛᵢ : Type} {OuterOStmtIn : Outer_ιₛᵢ → Type} [∀ i, OracleInterface (OuterOStmtIn i)]
    {Outer_ιₛₒ : Type} {OuterOStmtOut : Outer_ιₛₒ → Type} [∀ i, OracleInterface (OuterOStmtOut i)]
    {Inner_ιₛᵢ : Type} {InnerOStmtIn : Inner_ιₛᵢ → Type} [∀ i, OracleInterface (InnerOStmtIn i)]
    {Inner_ιₛₒ : Type} {InnerOStmtOut : Inner_ιₛₒ → Type} [∀ i, OracleInterface (InnerOStmtOut i)]
    (outerLangIn : Set (OuterStmtIn × (∀ i, OuterOStmtIn i)))
    (outerLangOut : Set (OuterStmtOut × (∀ i, OuterOStmtOut i)))
    (innerLangIn : Set (InnerStmtIn × (∀ i, InnerOStmtIn i)))
    (innerLangOut : Set (InnerStmtOut × (∀ i, InnerOStmtOut i)))
    (compatStmt :
      OuterStmtIn × (∀ i, OuterOStmtIn i) → InnerStmtOut × (∀ i, InnerOStmtOut i) → Prop)
    (lens : OracleStatement.Lens OuterStmtIn OuterStmtOut InnerStmtIn InnerStmtOut
                                    OuterOStmtIn OuterOStmtOut InnerOStmtIn InnerOStmtOut) :=
  Statement.Lens.IsSound outerLangIn outerLangOut innerLangIn innerLangOut compatStmt lens

Equiv.sumComm in Mathlib.Logic.Equiv.Sum

def ratchet (state : FSProverState U H R) :
    Except DomainSeparatorMismatch (FSProverState U H R) :=
  match state.hashState.ratchet with
  | .ok newHashState =>
    .ok { rng := state.rng, hashState := newHashState, nargString := state.nargString }
  | .error e => .error e

List.max in Init.Data.List.Basic

instance : Fintype (pSpec.MessageIdx) := Subtype.fintype (fun i => pSpec.dir i = .P_to_V)

Subtype in Init.Prelude

noncomputable def hasMutualCorrAgreement
  (Gen : ProximityGenerator ι F) [Fintype Gen.parℓ]
  (BStar : ℝ) (errStar : ℝ → ENNReal) :=
    haveI := Gen.Gen_nonempty
    ∀ (f : Gen.parℓ → ι → F) (δ : ℝ≥0) (_hδ : 0 < δ ∧ δ < 1 - BStar),
    Pr_{let r ←$ᵖ Gen.Gen}[ proximityCondition f δ r Gen.C ] ≤ errStar δ

instance {α : Type*} {n : ℕ} [VCVCompatible α] : VCVCompatible (Vector α n) where

noncomputable def ElocPolyF (ωs f : Fin n → F) (p : Polynomial F) : Polynomial F :=
  ElocPoly n (liftF ωs) (liftF f) p

Bool in Init.Prelude

private def k [Zero F] (B : Finset (Fin n → F)) : ℚ :=
  (1 : ℚ) / n * ∑ i, K B i 0

head in ToMathlib.Control.Comonad.Instances

structure BacktrackSequenceFamily (trace : QueryLog (duplexSpongeChallengeOracle StmtIn U))
    (state : CanonicalSpongeState U) where
   
  seqFamily : Finset (BacktrackSequence trace state)
   
  maximality : ∀ s ∈ seqFamily, ∀ s' ∈ seqFamily,
    (s.stmt ≠ s'.stmt) ∨ ¬ (s.inputState ⊆ s'.inputState) ∨ ¬ (s'.outputState ⊆ s.outputState)

def neg_descending (p : UniPoly R) : QuotientUniPoly R :=
  Quotient.mk _ (neg p)

instance : Zero (Cayley T) where
  zero := zero

@[reducible]
def index (op : MemoryWrite ι α) := op.1

@[inline, specialize]
def Reduction.runWithLog (stmt : StmtIn) (wit : WitIn)
    (reduction : Reduction oSpec StmtIn WitIn StmtOut WitOut pSpec) :
      OracleComp (oSpec ++ₒ [pSpec.Challenge]ₒ)
        (((FullTranscript pSpec × StmtOut × WitOut) × StmtOut) ×
          QueryLog (oSpec ++ₒ [pSpec.Challenge]ₒ) × QueryLog oSpec) := do
  
  let ⟨proverResult, proveQueryLog⟩ ← reduction.prover.runWithLog stmt wit
  let ⟨stmtOut, verifyQueryLog⟩ ←
    liftM (simulateQ loggingOracle (reduction.verifier.run stmt proverResult.1)).run
  return ⟨⟨proverResult, stmtOut⟩, proveQueryLog, verifyQueryLog⟩

noncomputable def definingPoly {F : Type*} [instField : Field F] (s : F)
  := X ^ 2 + C s * X + 1

[width_ne_zero : NeZero width]

noncomputable def listDecodingCollisionProbability
  (φ : ι ↪ F) (f : ι → F) (δ : ℝ) (s degree : ℕ)
  (h_nonempty : Nonempty (domainComplement φ)) : ENNReal :=
  Pr_{let r ←$ᵖ (Fin s → domainComplement φ)}[ ∃ (u u' : code φ degree),
                                    u.val ≠ u'.val ∧
                                    u.val ∈ relHammingBall (code φ degree) f δ ∧
                                    u'.val ∈ relHammingBall (code φ degree) f δ ∧
                                    ∀ i : Fin s,
                                    let uPoly := decodeLT u
                                    let uPoly' := decodeLT u'
                                    (uPoly : F[X]).eval (r i).1
                                      = (uPoly' : F[X]).eval (r i).1
                                    ]

noncomputable def distFromCode (u : n → R) (C : Set (n → R)) : ℕ∞ :=
  sInf {d | ∃ v ∈ C, hammingDist u v ≤ d}

Array.zipIdx in Init.Data.Array.Basic

OneHom in Mathlib.Algebra.Group.Hom.Defs

def evalSetY [DecidableEq F] (f : F[X][Y]) (P : Finset F) [Nonempty P] : Finset (Polynomial F) :=
  P.image (fun a => evalY a f)

def DVec {m : Type v} (α : m → Type u) : Type (max u v) := ∀ i, α i

ZMod.charP in Mathlib.Data.ZMod.Basic

inductive SkeletonInternalIndex : Skeleton → Type
  | ofInternal {left right} : SkeletonInternalIndex (Skeleton.internal left right)
  | ofLeft {left right : Skeleton} (idxLeft : SkeletonInternalIndex left) :
      SkeletonInternalIndex (Skeleton.internal left right)
  | ofRight {left right : Skeleton} (idxRight : SkeletonInternalIndex right) :
      SkeletonInternalIndex (Skeleton.internal left right)

noncomputable def fold
  {S : Finset ι} (φ : ι ↪ F) (f : ι → F) (k : ℕ) (α : F) : indexPow S φ k → F :=
    fun x => (xPoly f φ k x).eval α

def extract {n : ℕ} {α : Fin n → Sort*} (start stop : ℕ) (h1 : start ≤ stop) (h2 : stop ≤ n)
    (v : (i : Fin n) → α i) : (i : Fin (stop - start)) → α ⟨i + start, by admit /- proof elided -/
    ⟩ :=
  fun i ↦ v ⟨i + start, by admit /- proof elided -/
  ⟩

@[simp]
def finRangeTo {k : ℕ} (i : ℕ) : Finset (Fin k) :=
  (List.take i (List.finRange k)).toFinset

def BinaryTowerAux (k : ℕ) : (Σ' (F : Type 0), BinaryTowerResult F k) :=
  match k with
  | 0 => 
    let curBTField := GF(2)
    let newList : List.Vector (GF(2)) 1 := List.Vector.cons (1 : GF(2)) List.Vector.nil
    let specialElement : GF(2) := newList.1.headI
    let firstElementOfVecIsSpecialElement : newList.1.headI = specialElement := rfl
    let specialElementIs1 : specialElement = 1 := by admit /- proof elided -/

noncomputable def polyEvalLinearMap {L 𝔽q : Type*} [Field L] [Field 𝔽q] [Algebra 𝔽q L]
  (p : L[X]) (hp_add : IsLinearMap 𝔽q (fun x : L => p.eval x)) : L →ₗ[𝔽q] L :=
{
  toFun    := fun x => p.eval x,
  map_add' := hp_add.map_add,
  map_smul' := hp_add.map_smul
}

@[reducible]
def foldCommitOracleReduction (i : Fin ℓ)
    (hCR : isCommitmentRound ℓ ϑ i) :
  OracleReduction []ₒ
    (StmtIn := Statement (L := L) Context i.castSucc)
    (OStmtIn := OracleStatement 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ϑ i.castSucc)
    (WitIn := Witness (L := L) 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (ℓ:=ℓ) i.castSucc)
    (StmtOut := Statement (L := L) Context i.succ)
    (OStmtOut := OracleStatement 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ϑ i.succ)
    (WitOut := Witness (L := L) 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (ℓ:=ℓ) i.succ)
    (pSpec := pSpecFoldCommit 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) i) :=
  OracleReduction.append (oSpec:=[]ₒ)
    (pSpec₁ := pSpecFold (L:=L))
    (pSpec₂ := pSpecCommit 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) i)
    (R₁ := foldOracleReduction 𝔽q β (ϑ:=ϑ) (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (𝓑:=𝓑) i)
    (R₂ := commitOracleReduction 𝔽q β (ϑ:=ϑ) (h_ℓ_add_R_rate := h_ℓ_add_R_rate) i hCR)

instance : SMul R (UniPoly R) := ⟨UniPoly.smul⟩

Vector.take in Init.Data.Vector.Basic

state.zipWith (fun s d => sumAll + d * s) params.internalDiagVectors

instance : Unique (Fin 0 → α) where
  uniq v := by admit /- proof elided -/

class ProverOnly (pSpec : ProtocolSpec 1) extends ProverFirst pSpec

PFunctor in Mathlib.Data.PFunctor.Univariate.Basic

@[reducible]
def mk {R : Type*} (coeffs : Array R) : UniPoly R := coeffs

instance {i : Fin k} : ∀ j, OracleInterface ((pSpec D x s i).Message j)
  | ⟨0, h⟩ => nomatch h
  | ⟨1, _⟩ => by admit /- proof elided -/

instance [Zero T] [One T] [ToNat T] : NatPow (Cayley T) where
  pow := powNat

let f_bar_i := uniqueClosestCodeword 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate)
      (i := ⟨i, by admit /- proof elided -/
      ⟩) (h_i := by admit /- proof elided -/
      ) f_i
      h_dist_curr_lt
    let folded_f_i := iterated_fold 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate)
      (steps := ⟨steps, by admit /- proof elided -/
      ⟩) (i := ⟨i, by admit /- proof elided -/
      ⟩)
      (h_i_add_steps := by admit /- proof elided -/
      ) f_i challenges
    let folded_f_bar_i := iterated_fold 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate)
      (steps := ⟨steps, by admit /- proof elided -/
      ⟩) (i := ⟨i, by admit /- proof elided -/
      ⟩)
      (h_i_add_steps := by admit /- proof elided -/
      ) f_bar_i challenges

List.foldl in Init.Prelude

def OracleMessages (pSpec : ProtocolSpec n) [OracleInterfaces pSpec] : Type :=
  ∀ i, pSpec.OracleMessage i

def SkeletonNodeIndex.rightChild {s : Skeleton} (idx : SkeletonNodeIndex s) :
    Option (SkeletonNodeIndex s) :=
  match idx with
  | SkeletonNodeIndex.ofLeaf => none
  | @SkeletonNodeIndex.ofInternal left right =>
    some (SkeletonNodeIndex.ofRight (getRootIndex right))
  | SkeletonNodeIndex.ofLeft idxLeft =>
    idxLeft.rightChild.map (SkeletonNodeIndex.ofLeft)
  | SkeletonNodeIndex.ofRight idxRight =>
    idxRight.rightChild.map (SkeletonNodeIndex.ofRight)

def nonLastBlockOracleReduction (bIdx : Fin (ℓ / ϑ - 1)) :=
  let stmt : Fin (ϑ - 1 + 1) → Type :=
    fun i => Statement (L := L) (ℓ := ℓ) Context ⟨bIdx * ϑ + i, bIdx_mul_ϑ_add_i_cast_lt_ℓ_succ bIdx i⟩
  let oStmt := fun i: Fin (ϑ - 1 + 1) =>
    OracleStatement 𝔽q β ϑ ⟨bIdx * ϑ + i, bIdx_mul_ϑ_add_i_cast_lt_ℓ_succ bIdx i⟩
  let wit := fun i: Fin (ϑ - 1 + 1) =>
    Witness (L := L) 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) (ℓ:=ℓ)
      ⟨bIdx * ϑ + i, bIdx_mul_ϑ_add_i_cast_lt_ℓ_succ bIdx i⟩
  let firstFoldRelayRoundsOracleReduction :=
    OracleReduction.seqCompose (oSpec := []ₒ)
      (Stmt := stmt)
      (OStmt := oStmt)
      (Wit := wit)
      (pSpec := fun i => pSpecFoldRelay (L:=L))
      (R := fun i => by admit /- proof elided -/
      )

def finUInt16Equiv : Fin (2 ^ 16) ≃ UInt16 where
  toFun := fun i => UInt16.ofFin i
  invFun := fun u => u.toFin
  left_inv _ := rfl
  right_inv _ := rfl

def distanceLE (Message : Type*) [O : OracleInterface Message]
    [Fintype (O.Query)] [DecidableEq (O.Response)] (d : ℕ) : Prop :=
  ∀ a b : Message, a ≠ b → #{q | OracleInterface.answer a q = OracleInterface.answer b q} ≤ d

embed := sorry

@[inline, reducible]
def toContext :
    Context.Lens (OuterStmtIn × (∀ i, OuterOStmtIn i)) (OuterStmtOut × (∀ i, OuterOStmtOut i))
                (InnerStmtIn × (∀ i, InnerOStmtIn i)) (InnerStmtOut × (∀ i, InnerOStmtOut i))
                OuterWitIn OuterWitOut InnerWitIn InnerWitOut :=
  ⟨lens.stmt, lens.wit⟩

def BBF_SumcheckMultiplierParam : SumcheckMultiplierParam L ℓ (SumcheckBaseContext L ℓ) :=
  { multpoly := fun ctx => BBF_eq_multiplier ctx.t_eval_point }

Fin.add in Init.Data.Fin.Basic

def findFinIdx (p : α → Bool) (l : List α) : Fin (l.length + 1) :=
  ⟨List.findIdx' p l,
    Nat.lt_succ_of_le (by admit /- proof elided -/
    )⟩

instance [Zero T] [DecidableEq T] [ToNat T] : Div (Cayley T) where
  div := div

Gen_α : ∀ i : Fin (M + 1), ∀ j : Fin ((P.foldingParam i) + 1),
    ProximityGenerator (indexPowT (S i) (P.φ i) j) F :=
      fun i j => RSGenerator.genRSC (parℓ_type i j) (φ i j) (P.varCount i - j) (exp i j)

def dedup {ι : Type} (spec : OracleSpec ι) : SimOracle.Stateless (spec ++ₒ spec) spec where
  impl
  | query (.inl i) t => query i t
  | query (.inr i) t => query i t

def degCor
  (φ : ι ↪ F) (dstar degree : ℕ) (r : F) (f : ι → F) (x : ι) : F :=
    f x * ∑ l ∈ range (dstar - degree + 1), ((φ x) * r) ^ l

MvPolynomial.support in Mathlib.Algebra.MvPolynomial.Basic

Nat.card in Mathlib.SetTheory.Cardinal.Finite

def oracleFoldingConsistencyProp (i : Fin (ℓ + 1)) (challenges : Fin i → L)
    (oStmt : ∀ j, (OracleStatement 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ϑ i) j) : Prop :=
  ∀ (j : Fin (toOutCodewordsCount ℓ ϑ i)) (hj : j.val + 1 < toOutCodewordsCount ℓ ϑ i),
    
    have h_k_bound := oracle_block_k_bound (ℓ := ℓ) (ϑ := ϑ) (i := i) (j := j)
    have h_k_next_le_i := oracle_block_k_next_le (ℓ := ℓ) (ϑ := ϑ) (i := i) (j := j) (hj := hj)
    
    isCompliant (i := ⟨j.val * ϑ, by admit /- proof elided -/
    ⟩) (steps := ϑ)
      (h_i_add_steps := by admit /- proof elided -/
      )
      (f_i := oStmt ⟨j.val, by admit /- proof elided -/
      ⟩)
      (f_i_plus_steps := getNextOracle 𝔽q β i oStmt j hj)
      (challenges := getFoldingChallenges (r := r) (𝓡 := 𝓡) i challenges (k := j.val * ϑ)
        (h := h_k_next_le_i))

Prod in Init.Prelude

Finset.Iio in Mathlib.Order.Interval.Finset.Defs

def liftingLens :
  OracleContext.Lens
    ((Fin m → F) × Fri.Spec.Statement F (0 : Fin (k + 1))) (Fri.Spec.FinalStatement F k)
    (Fri.Spec.Statement F (0 : Fin (k + 1))) (Fri.Spec.FinalStatement F k)
    (OracleStatement D x m) (Fri.Spec.FinalOracleStatement D x s)
    (Fri.Spec.OracleStatement D x s 0) (Fri.Spec.FinalOracleStatement D x s)
    (Fri.Spec.Witness F s d 0) (Fri.Spec.Witness F s d (Fin.last (k + 1)))
    (Fri.Spec.Witness F s d 0) (Fri.Spec.Witness F s d (Fin.last (k + 1))) where
  stmt := Witness.InvLens.ofOutputOnly <| fun ⟨⟨cs, stmt⟩, ostmt⟩ =>
    ⟨
      stmt,
      fun j v =>
          have : v.1 ∈ Fri.CosetDomain.evalDomain D x 0 := by admit /- proof elided -/
    ⟩
  wit  := Witness.Lens.id

AddMonoidAlgebra in Mathlib.Algebra.MonoidAlgebra.Defs

alias E := combined

def LeafData.ofFun {α : Type} (s : Skeleton)
    (f : SkeletonLeafIndex s → α) : LeafData α s :=
  match s with
  | .leaf => LeafData.leaf (f SkeletonLeafIndex.ofLeaf)
  | .internal l r =>
      LeafData.internal
        (LeafData.ofFun l (fun idx => f (SkeletonLeafIndex.ofLeft idx)))
        (LeafData.ofFun r (fun idx => f (SkeletonLeafIndex.ofRight idx)))

@[ext]
structure Verifier {ι : Type} (oSpec : OracleSpec ι)
    (StmtIn StmtOut : Type) {n : ℕ} (pSpec : ProtocolSpec n) where
  verify : StmtIn → FullTranscript pSpec → OracleComp oSpec StmtOut

def masterKStateProp (stmtIdx : Fin (ℓ + 1))
    (oracleIdx : Fin (ℓ + 1))
    (h_le : oracleIdx.val ≤ stmtIdx.val) (stmt : Statement (L := L) Context stmtIdx)
    (wit : Witness (L := L) 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) stmtIdx)
    (oStmt : ∀ j, (OracleStatement 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ϑ (i := oracleIdx) j))
    (localChecks : Prop := True) : Prop :=
  let oracleWitnessConsistency: Prop := oracleWitnessConsistency (mp := mp) (𝓑 := 𝓑) 𝔽q β
    stmtIdx oracleIdx h_le stmt wit oStmt
  let badEventExists := badEventExistsProp (ϑ := ϑ) 𝔽q β oracleIdx
    (challenges := Fin.take (m := oracleIdx) (v := stmt.challenges) (h := by admit /- proof elided -/
    ))
    (oStmt := oStmt)
  localChecks ∧ (badEventExists ∨ oracleWitnessConsistency)

absurd in Init.Prelude

def Option.doubleBind {α β γ : Type} (f : α → β → Option γ)
    (x : Option α) (y : Option β) : Option γ :=
  match x, y with
  | none, _ => none
  | _, none => none
  | some a, some b => f a b

Matrix.submatrix in Mathlib.LinearAlgebra.Matrix.Defs

@[inline]
def smul [Mul R] (r : R) (p : MlPoly R n) : MlPoly R n := p.map (fun a => r * a)

def twoLevelData {α} (k0 k1 : ℕ)
    (root : α)
    (lvl1 : Fin k0 → α)
    (lvl2 : (i : Fin k0) → Fin k1 → α) :
    ArityTree.Data α (twoLevelSkel k0 k1) :=

def vflatten {m : ℕ} {n : Fin m → ℕ} (v : (i : Fin m) → Fin (n i) → α) :
    Fin (vsum n) → α :=
  dflatten v

@[simp]
abbrev OracleStatement.AfterSecondSumcheck : R1CS.MatrixIdx ⊕ R1CS.MatrixIdx ⊕ Fin 1 → Type :=
  Sum.elim (EvalClaim R) (OracleStatement.AfterFirstSumcheck R pp)

Nat.reducePow in Lean.Meta.Tactic.Simp.BuiltinSimprocs.Nat

@[inline, specialize, simp]
def oracleReduction : OracleReduction oSpec
    Statement OStatement Witness Statement OStatement Witness !p[] := OracleReduction.id

@[reducible, inline, specialize]
def challengeOracleInterfaceSR (StmtIn : Type) (pSpec : ProtocolSpec n) :
    ∀ i, OracleInterface (pSpec.Challenge i) := fun i =>
  { Query := StmtIn × pSpec.MessagesUpTo i.1.castSucc
    Response := pSpec.Challenge i
    answer := fun c _ => c }

OracleSpec.append in VCVio.OracleComp.OracleSpec

IntCast in Init.Data.Int.Basic

protected def OracleProver.id :
    OracleProver oSpec Statement OStatement Witness Statement OStatement Witness !p[] :=
  Prover.id

[numFullRounds_ne_zero : NeZero numFullRounds]

def SumFunEquivProd (α β γ : Type) : ((α ⊕ β) → γ) ≃ (α → γ) × (β → γ) :=
{ toFun := fun f => (fun a => f (.inl a), fun b => f (.inr b))
  , invFun := fun p x => match x with | .inl a => p.fst a | .inr b => p.snd b
  , left_inv := by admit /- proof elided -/

instance (priority := low) : DCast₂ α β γ where
  dcast₂ ha hb c := by admit /- proof elided -/

class GenMutualCorrParams (P : Params ι F) (S : ∀ i : Fin (M + 1), Finset (ι i)) where

@[reducible, simp]
def oraclePSpec : ProtocolSpec 1 := ⟨!v[.P_to_V], !v[Witness]⟩

def hconcat {n : ℕ} {α : Fin n → Sort u} {β : Sort u} (u : (i : Fin n) → α i) (a : β) :
    (i : Fin (n + 1)) → Fin.vconcat α β i :=
  fconcat (F := id) u a

let transposedMatrix := Vector.Matrix.transpose chunksAfterM4

def toStatement (stmt : FinalSumcheckStatementOut (L := L) (ℓ := ℓ)) :
  Statement (L := L) (Context := SumcheckBaseContext L ℓ) (Fin.last ℓ)  :=
  {
    sumcheck_target := stmt.sumcheck_target,
    challenges := stmt.challenges,
    ctx := stmt.ctx
  }

instance : ∀ i, VCVCompatible ((pSpec Witness).Challenge i) | ⟨0, h⟩ => nomatch h

Algebra.TensorProduct.comm in Mathlib.RingTheory.TensorProduct.Maps

RingHom in Mathlib.Algebra.Ring.Hom.Defs

def perfectCorrectness (scheme : Scheme oSpec Data Randomness Commitment pSpec) : Prop :=
  correctness scheme 0

instance instZeroConcreteBTField (k : ℕ) : Zero (ConcreteBTField k) where
  zero := zero

Algebra.algebraMap in Mathlib.Algebra.Algebra.Defs

def mul_by_2 (s : Finset ℕ) : Finset ℕ :=
  s.map ⟨fun n => 2 * n, by admit /- proof elided -/
  ⟩

exp : ∀ i : Fin (k + 1), (parℓ_type i) ↪ ℕ

@[simp]
abbrev LinearCombinationChallenge : Type := R1CS.MatrixIdx → R

class NonBinaryField (F : Type*) extends Field F where
  char_neq_2 : (2 : F) ≠ 0

let get_rᵢ' := fun (m: Fin (2 + 1)) (tr: Transcript m pSpecFold) (hm: 2 ≤ m.val) =>
    let ⟨msgsUpTo, chalsUpTo⟩ := Transcript.equivMessagesChallenges (k := m)
      (pSpec := pSpecFold (L := L)) tr
    let i_msg1 : ((pSpecFold (L := L)).take m m.is_le).MessageIdx :=
      ⟨⟨0, Nat.lt_of_succ_le (Nat.le_trans (by admit /- proof elided -/
      ) hm)⟩, by admit /- proof elided -/
      ⟩
    let h_i : L⦃≤ 2⦄[X] := msgsUpTo i_msg1
    let i_msg2 : ((pSpecFold (L := L)).take m m.is_le).ChallengeIdx :=
      ⟨⟨1, Nat.lt_of_succ_le hm⟩, by admit /- proof elided -/
      ⟩
    let r_i' : L := chalsUpTo i_msg2
    r_i'

noncomputable def monomialOfNat (i : ℕ) : (Fin n) →₀ ℕ :=
  Finsupp.onFinset (s:=Finset.univ (α:=Fin n)) (fun j => Nat.getBit j.val i) (by admit /- proof elided -/
    )

instance (k : ℕ) : Add (ConcreteBTField k) where
  add := add

IsField in Mathlib.Algebra.Field.IsField

@[reducible, simp]
def relOut : Set (Statement × Unit) := Set.univ

def toEvalsZeroOne (p : MvPolynomial σ R) : (σ → Fin 2) → R :=
  fun x => eval (x : σ → R) p

output := pure

@[reducible, simp] def StmtOut := Query OStatement × Response OStatement

@[inline, specialize, simp]
def oracleVerifier : OracleVerifier oSpec Statement OStatement Statement OStatement !p[] :=
  OracleVerifier.id

def finalize (ds : DomainSeparator U H) : Array Op :=
  let parts := ds.io.splitOn SEP_BYTE
  
  let parseDigits (cs : List Char) : Nat × List Char :=
    let rec go : Nat → List Char → Nat × List Char
    | acc, [] => (acc, [])
    | acc, c :: rest =>
      if c.isDigit then
        let d := (c.toNat - '0'.toNat)
        go (acc * 10 + d) rest
      else
        (acc, c :: rest)
    go 0 cs
  let parsePart (s : String) : Option Op :=
    match s.data with
    | [] => none
    | id :: rest =>
      let (n, _rest) := parseDigits rest
      match id with
      | 'A' => if n = 0 then none else some (Op.Absorb n)
      | 'S' => if n = 0 then none else some (Op.Squeeze n)
      | 'R' => some Op.Ratchet
      | 'H' => some Op.Hint
      | _ => none
  let opsList := (parts.drop 1).foldl (fun acc p =>
      match parsePart p with
      | some op => acc.push op
      | none => acc) (#[] : Array Op)
  
  let simplify (acc : Array Op) (op : Op) : Array Op :=
    match acc.back? with
    | some (Op.Absorb a) =>
        match op with
        | Op.Absorb b => acc.pop.push (Op.Absorb (a + b))
        | _ => acc.push op
    | some (Op.Squeeze a) =>
        match op with
        | Op.Squeeze b => acc.pop.push (Op.Squeeze (a + b))
        | _ => acc.push op
    | _ => acc.push op
  opsList.foldl simplify (#[] : Array Op)

instance {s} : Functor (fun α => LeafData α s) where
  map f x := x.map f

Preorder in Mathlib.Order.Defs.PartialOrder

let ⟨s, d⟩ := factorOutTwos (n - 1)
  for a in millerRabinBases do
    if a % n == 0 then
      continue

def uniqueClosestCodeword
  (i : Fin (ℓ + 1)) (h_i : i < ℓ + 𝓡)
  (f : OracleFunction 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ⟨i, i.isLt⟩)
  (h_within_radius : hammingClose 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) i f) :
  OracleFunction 𝔽q β (h_ℓ_add_R_rate := h_ℓ_add_R_rate) ⟨i, i.isLt⟩ :=

tag in Examples.FrankingProtocol

def rationalRoot (H : F[X][Y]) (z : F) : Type :=
  {t_z : F // evalEval z t_z H = 0}

Quotient.lift in Init.Core

instance instDCast : DCast Nat Fin where
  dcast h := Fin.cast h
  dcast_id := by admit /- proof elided -/

class IsSecureWithGap
    (completeRelation : Set ((Statement × ∀ i, OStatement i) × Witness))
    (soundRelation : Set ((Statement × ∀ i, OStatement i) × Witness))
    (ε_rbr : vPSpec.ChallengeIdx → ℝ≥0)
    (vectorIOP : VectorIOP Statement OStatement Witness vPSpec A) where

φ : ∀ i : Fin (M + 1), ∀ j : Fin ((P.foldingParam i) + 1), (indexPowT (S i) (P.φ i) j) ↪ F

class VCVCompatible (α : Type*) extends Fintype α, Inhabited α where
  [type_decidableEq' : DecidableEq α]

@[reducible]
def addSalt (pSpec : ProtocolSpec n) (Salt : pSpec.MessageIdx → Type) :
    ProtocolSpec n :=
  ⟨pSpec.dir, fun i => match hDir : pSpec.dir i with
    | .P_to_V => (pSpec.«Type» i) × Salt ⟨i, hDir⟩
    | .V_to_P => pSpec.«Type» i⟩

def Option.doubleBind_v2 {α β γ : Type} (f : α → β → Option γ)
    (x : Option α) (y : Option β) : Option γ := do
  let a ← x
  let b ← y
  f a b

def map {α β : Fin n → Sort*} (f : (i : Fin n) → α i → β i) (a : (i : Fin n) → α i) :
    (i : Fin n) → β i := fun i => f i (a i)

def mul (m n : ChurchNat α) : ChurchNat α := fun f => n (m f)

List.Vector.snoc in Mathlib.Data.Vector.Snoc

instance instST₁ : ∀ i, SelectableType ((⟨!v[.P_to_V], !v[R⦃≤ deg⦄[X]]⟩ ++ₚ !p[]).Challenge i) :=
  instSelectableTypeChallengeAppend

def Fin2ToF2 (𝔽q : Type*) [Ring 𝔽q] (k : Fin 2) : 𝔽q :=
  if k = 0 then 0 else 1

instance {s} : LawfulFunctor (fun α => InternalData α s) :=

context in Examples.FrankingProtocol

abbrev ScalarField := ZMod scalarFieldSize

e
</all_available_defs>

<all_available_lemmas>
...

theorem List.getElem_append_left{α : Type u_1} {l₁ l₂ : List α} {i : Nat} (hn : i < l₁.length) :\n(l₁ ++ l₂)[i] = l₁[i]

@[simp]
theorem ranges_succ {a : ℕ} {l : List ℕ} :
    List.ranges (a :: l) = range a :: l.ranges.map (map (a + ·))

theorem eq_zero_of_degreeOf_lt_card_of_eval_eq_zero {p : R[X σ]} (S : σ → Finset R)
    (hDegree : ∀ i, p.degreeOf i < #(S i))
    (hEval : ∀ x ∈ piFinset fun i ↦ S i, eval x p = 0) : p = 0

foldSet ≠ listHamming
                    ] < (∑ i : Fin (k + 1),
                          params.errStar i (params.Gen_α i).C (params.Gen_α i).parℓ δ)

lemma add_two_pow_of_getBit_eq_zero_lt_two_pow {n m i : ℕ} (h_n: n < 2^m) (h_i: i < m)
  (h_getBit_at_i_eq_zero: getBit i n = 0) :
  n + 2^i < 2^m

@[simp]
lemma bIdx_mul_ϑ_add_i_cast_lt_ℓ_succ (bIdx : Fin (ℓ / ϑ - 1)) (i : Fin (ϑ - 1 + 1))
    : ↑bIdx * ϑ + i < ℓ + 1

theorem matchSize_toList {a b : Array α} {unit : α} :
    matchSize a b unit =
      let (a', b') := List.matchSize a.toList b.toList unit
      (mk a', mk b')

lemma not_outOfOrder_of_not_combined (h : ¬ E trace) : ¬ E_time trace state

@[simp]
theorem vcons_fin_zero (a : α) (v : Fin 0 → α) : a ::ᵛ v = fun i => match i with

theorem sub_add_eq_sub_sub_rev (a b c : Nat) (h1 : c ≤ b) (h2 : b ≤ a) :
  a - b + c = a - (b - c)

theorem fixFirstVariablesOfMQP_degreeLE {deg : ℕ} (v : Fin (ℓ + 1)) {challenges : Fin v → L}
    {poly : L[X Fin ℓ]} (hp : poly ∈ L⦃≤ deg⦄[X Fin ℓ]) :
    fixFirstVariablesOfMQP ℓ v poly challenges ∈ L⦃≤ deg⦄[X Fin (ℓ - v)]

theorem finrank_degreeLT_n (n : ℕ) : Module.finrank L (L⦃< n⦄[X]) = n

@[simp]
theorem dcast₃_trans (ha : a = a') (ha' : a' = a'')
    (hb : dcast ha b = b') (hb' : dcast ha' b' = b'')
    (hc : dcast₂ ha hb c = c') (hc' : dcast₂ ha' hb' c' = c'') :
    dcast₃ ha' hb' hc' (dcast₃ ha hb hc d) =
    dcast₃ (ha.trans ha') (by simp [← hb', ← hb]) (by simp [← hc', ← hc]) d

omit [NeZero r] in
theorem hβ_lin_indep_concrete (k : ℕ) :
    letI := ConcreteBTFieldAlgebra (l:=0) (r:=k) (h_le:=by omega)
    LinearIndependent (R := ConcreteBTField 0)
      (v := computableBasisExplicit k)

lemma toOutCodewordsCount_last ℓ ϑ : toOutCodewordsCount ℓ ϑ (Fin.last ℓ) = ℓ / ϑ

lemma eq_degree_of_equiv [LawfulBEq R] {p q : UniPoly R} : equiv p q → p.degree = q.degree

@[simp]
lemma addSalt_Type (i : Fin n) :
    (pSpec.addSalt Salt).«Type» i = match hDir : pSpec.dir i with

theorem vflatten_eq_vappend_last {m : ℕ} {n : Fin (m + 1) → ℕ}
    {v : (i : Fin (m + 1)) → Fin (n i) → α} :
    vflatten v =
      vappend (vflatten (fun i => v i.castSucc)) (v (last _)) ∘ Fin.cast vsum_castSucc

lemma split_join_via_add_smul_eq_iff_split (k : ℕ) (h_pos : k > 0)
    (hi_btf lo_btf : BTField (k - 1)) :
    split (k:=k) (h_k:=h_pos) (⋘ hi_btf, lo_btf ⋙) = (hi_btf, lo_btf)

@[simp] theorem equiv_symm {p q : UniPoly Q} : equiv p q → equiv q p

lemma exists_points_with_large_matching_subset
  {ωs : Fin n ↪ F}
  (h_gs : ModifiedGuruswami m n k ωs Q u₀ u₁)
  {x : Fin n}
  {D : ℕ}
  (hD : D ≥ Bivariate.totalDegree (H k δ x₀ h_gs))
  :
  ∃ Dtop : Finset (Fin n),
    Dtop.card = k + 1 ∧
    ∀ x ∈ Dtop,
      (matching_set_at_x k δ h_gs x).card >
        (2 * k + 1)
        * (Bivariate.natDegreeY <| H k δ x₀ h_gs)
        * (Bivariate.natDegreeY <| R k δ x₀ h_gs)
        * D

@[simp]
theorem fcons_zero {β : Fin n → A} (a : F α) (b : (i : Fin n) → F (β i)) :
    fcons a b 0 = cast (by simp [vcons_zero]) a

@[simp]
theorem cast_idx_symm {i : ChallengeIdx pSpec₂} :
    pSpec₁.Challenge (i.cast hn.symm (cast_symm hSpec)) = pSpec₂.Challenge i

lemma generalised_round_consistency_completeness
  {𝔽 : Type} [inst1 : Field 𝔽] [DecidableEq 𝔽] {f : Polynomial 𝔽}
  {n : ℕ} [inst : NeZero n]
  {γ : 𝔽}
  {s₀ : 𝔽}
  {ω : Fin n ↪ 𝔽}
  (h : ∀ i, (ω i) ^ n = 1)
  (h₁ : s₀ ≠ 0)
  :
    roundConsistencyCheck
      γ
      (List.map (fun i => (ω i * s₀, f.eval (ω i * s₀))) (List.finRange n))
      ((foldNth n f γ).eval (s₀^n)) = true

@[simp]
lemma zero_mem_relHammingDistRange : 0 ∈ relHammingDistRange ι

@[ext]
theorem ext' {a b : AssocNat} (h : a 0 = b 0) : a = b

lemma zsmul_neg' {k : ℕ} (n : ℕ) (a : ConcreteBTField k) :
  (if ((Int.negSucc n) : ℤ) % (2 : ℤ) = (0 : ℤ) then zero else a) =
    neg (if (↑n.succ : ℤ) % (2 : ℤ) = (0 : ℤ) then zero else a)

lemma toOutCodewordsCount_mul_ϑ_eq_i_succ (i : Fin ℓ) (hCR : isCommitmentRound ℓ ϑ i) :
  (toOutCodewordsCount ℓ ϑ i.castSucc) * ϑ = i.val + 1

theorem rtake_eq_take_rev {α : Sort*} (m : ℕ) (h : m ≤ n) (v : Fin n → α) :
    rtake m h v = (take m h (v ∘ Fin.rev)) ∘ Fin.rev

theorem dappend_succ {motive : Fin (m + (n + 1)) → Sort u}
    (u : (i : Fin m) → motive (castAdd (n + 1) i))
    (v : (i : Fin (n + 1)) → motive (natAdd m i)) :
    dappend (motive := motive) u v =
      (dappend u (fun i => v (castSucc i))) :+ᵈ⟨motive⟩ (v (last n))

lemma zipWith_size {R} {f : R → R → R} {a b : Array R} (h : a.size = b.size) :
    (Array.zipWith f a b).size = a.size

theorem support_C_mul_le (p : MvPolynomial σ R) (r : R) : (C r * p).support ⊆ p.support

private lemma Bi_biUnion_F2i :
  Bi B i = Finset.univ.biUnion (F2i B i)

lemma and_shl_eq_zero_of_lt_two_pow {a n b : ℕ} (hb : b < 2 ^ n) : (a <<< n) &&& b = 0

beq_iff_eq in Init.Core

@[simp]
lemma mul_by_empty :
    mul_by_2 ∅ = ∅

theorem unique_linear_decomposition_succ (k : ℕ) :
  ∀ (x : BTField (k+1)), ∃! (p : BTField k × BTField k),
    x = ⋘ p.1, p.2 ⋙

lemma getBit_of_highBits_no_shl {n: ℕ} (numLowBits : ℕ) :
    ∀ k, getBit k (getHighBits_no_shl numLowBits n)
  = getBit (k + numLowBits) (n)

theorem reduction_perfectCompleteness (hInit : init.neverFails) :
    (reduction R n deg D oSpec i).perfectCompleteness init impl
    (relationRound R n deg D i.castSucc) (relationRound R n deg D i.succ)

theorem ZMod.powNeOfPowMod :
    ∀ {n a' q c : ℕ} (a : ZMod n), (a' : ZMod n) = a → decide (n ≥ 2) = true →
      Nat.mod (Nat.pow a' ((n - 1) / q)) n = c → decide (c ≠ 1) = true → a ^ ((n - 1) / q) ≠ 1

lemma sDomain_eq_image_of_upper_span (i : Fin r) (h_i : i < ℓ + R_rate) :
    let V_i := Submodule.span 𝔽q (Set.range (sBasis β h_ℓ_add_R_rate i h_i))
    let W_i_map := polyEvalLinearMap (normalizedW 𝔽q β i)
      (normalizedW_is_additive 𝔽q β i)
    sDomain 𝔽q β h_ℓ_add_R_rate i
    = Submodule.map W_i_map V_i

theorem prime_101 : Nat.Prime 101

lemma W_prod_comp_decomposition
    (i : Fin r) (hi : i > 0) :
    (W 𝔽q β i) = ∏ c: 𝔽q, (W 𝔽q β (i-1)).comp (X - C (c • β (i-1)))

@[simp]
theorem oracleReduction_completeness (h : init.neverFails) :
    (oracleReduction oSpec Statement OStatement Witness).perfectCompleteness init impl oRelIn
    (toORelOut oRelIn)

theorem oracleReduction_rbr_knowledge_soundness : True

@[simp]
theorem rtake_append_right (T : FullTranscript pSpec₁) (T' : FullTranscript pSpec₂) :
    (T ++ₜ T').rtake n (Nat.le_add_left n m) =
      T'.cast rfl (by simp [ProtocolSpec.append])

theorem take_drop_append {α : Sort*} (m : ℕ) (h : m ≤ n) (v : Fin n → α) :
    Fin.append (take m h v) (drop m h v) = fun i => v (i.cast (by omega))

lemma isPrimitiveRoot_twoAdicGenerator (bits : Fin (twoAdicity + 1)) :
    IsPrimitiveRoot (twoAdicGenerators[bits]) (2 ^ (bits : Nat))

theorem eq_zero_or_eq_one {a : ConcreteBTField 0} : a = zero ∨ a = one

lemma natDeg_sum_eq_of_unique {α : Type} {s : Finset α} {f : α → F[X]} {deg : ℕ}
  (mx : α) (h : mx ∈ s) :
    (f mx).natDegree = deg →
    (∀ y ∈ s, y ≠ mx → (f y).natDegree < deg ∨ f y = 0) →
    (∑ x ∈ s, f x).natDegree = deg

lemma getBit_of_multiple_of_power_of_two {n p : ℕ}: ∀ k,
  getBit (k) (2^p * n) = if k < p then 0 else getBit (k-p) n

lemma galois_eval_in_BTField
    {curBTField : Type*} [Field curBTField]
    (u : curBTField) (t1 : curBTField) -- here t1 is already lifted to curBTField
    (k : ℕ)
    (sumZeroIffEq : ∀ (x y : curBTField), x + y = 0 ↔ x = y)
    (prevSpecialElementNeZero : t1 ≠ 0)
    (u_plus_inv_eq_t1 : u + u⁻¹ = t1)
    (h_u_square : u^2 = u*t1 + 1)
    (h_t1_pow : t1^(2^(2^k)-1) = 1 ∧ (t1⁻¹)^(2^(2^k)-1) = 1)
    (h_t1_pow_2_pow_2_pow_k :  t1^(2^(2^k)) = t1)
    (h_t1_inv_pow_2_pow_2_pow_k :  (t1⁻¹)^(2^(2^k)) = t1⁻¹)
    (trace_map_at_inv : ∑ i ∈ Finset.range (2 ^ k), t1⁻¹ ^ (2 ^ i) = 1) :
    u^(2^(2^k)) = u⁻¹

lemma discr_of_irred_components_nonzero
  (h_gs : ModifiedGuruswami m n k ωs Q u₀ u₁)
  : ∃ x₀,
      ∀ R ∈ (irreducible_factorization_of_gs_solution h_gs).choose_spec.choose,
      Bivariate.evalX x₀ (Bivariate.discr_y R) ≠ 0

lemma cast_mul (m n : ℕ) {x y : ConcreteBTField m} (h_eq : m = n) :
  (cast (by exact cast_ConcreteBTField_eq m n h_eq) (x * y)) =
  (cast (by exact cast_ConcreteBTField_eq m n h_eq) x) *
  (cast (by exact cast_ConcreteBTField_eq m n h_eq) y)

lemma Z_square_eq (k : ℕ) (prevBTFieldProps : ConcreteBTFieldProps (k := k))
    (curBTFieldProps : ConcreteBTFieldProps (k := (k + 1))) :
  letI : Field (ConcreteBTField (k + 1)) := mkFieldInstance curBTFieldProps
  (Z (k + 1)) ^ 2 = 《 Z (k), 1 》

lemma schwartz_zippel' {p : MvPolynomial σ R} (hp : p ≠ 0) (S : σ → Finset R) :
    #{x ∈ Finset.pi p.vars S | eval (extendDomain x) p = 0} / ∏ i ∈ p.vars, (#(S i) : ℚ≥0)
      ≤ ∑ i ∈ p.vars, (p.degreeOf i / #(S i) : ℚ≥0)

@[simp]
theorem embedSum_splitSum {m : ℕ} {n : Fin m → ℕ} (k : Fin (vsum n)) :
    embedSum (splitSum k).1 (splitSum k).2 = k

theorem mul_two (n : ChurchNat α) : mul n two = add n n

theorem vconcat_right_injective (v : Fin n → α) : Function.Injective (vconcat v)

theorem decoder_dist_impl_mem
  {k r D e : ℕ}
  (h_e : e ≤ n - Real.sqrt (k * n))
  {ωs : Fin n ↪ F}
  {f : Fin n → F}
  {p : F[X]}
  (h_dist : Δ₀(f, p.eval ∘ ωs) ≤ e)
  :
  p ∈ decoder k r D e ωs f

theorem completeness [DecidableEq α] [SelectableType α] {s}
    (leaf_data_tree : LeafData α s) (idx : BinaryTree.SkeletonLeafIndex s)
    (preexisting_cache : (spec α).QueryCache) :
    (((do
      let cache ← buildMerkleTree leaf_data_tree
      let proof := generateProof cache idx
      let _ ← verifyProof idx (leaf_data_tree.get idx) (cache.getRootValue) proof
      ).simulateQ (randomOracle)).run preexisting_cache).neverFails

theorem foldr_split_outer {α : Type u} {β : Type v} (f : α → β → β) (init : β)
    (l : List α) (h : l ≠ []): foldr (f:=f) (init:=init) (l)
    = f (l.head (by omega)) (foldr (f:=f) (init:=init) (l.tail))

lemma and_two_pow_eq_zero_of_getBit_0 {n i : ℕ} (h_getBit : getBit i n = 0)
    : n &&& (2 ^ i) = 0

@[simp]
theorem removeNth_zero : removeNth 0 s = tail s

@[simp]
theorem splitSum_succ {n : Fin (m + 1) → ℕ} {k : Fin (vsum n)} :
    splitSum k = Fin.dappend
      (fun k => ⟨0, k⟩)
      (fun k => ⟨(splitSum k).1.succ, (splitSum k).2⟩)
      k

lemma probOfBadPts {deg : ℕ} {α : ι ↪ F} {e : ℕ} {U : Matrix κ ι F}
  (he : (e : ℚ) < (Code.minDist (RScodeSet α deg) : ℚ) / 3)
  (hU : e < Δ(U, matrixSubmoduleOfLinearCode κ (ReedSolomon.code α deg))) :
  (PMF.uniformOfFintype (Matrix.rowSpan U)).toOuterMeasure
    { w | distFromCode (n := ι) (R := F) w (ReedSolomon.code α deg) ≤ e }
  ≤ (Code.minDist (RScodeSet α deg) : ℝ≥0) /(Fintype.card F : ℝ≥0)

theorem prod_poly_sub_C_eq_poly_pow_card_sub_poly_in_L
  (p : L[X]) :
  (∏ c ∈ (Finset.univ : Finset Fq), (p - Polynomial.C (algebraMap Fq L c))) =
    p^(Fintype.card Fq) - p

omit [Finite F] in
lemma pow_lift : ∀ {a : Fˣ} {i : ℕ} (s : ℕ),
    a ∈ evalDomain D x i → a ^ (2 ^ s) ∈ evalDomain D x (i + s)

theorem two_le_two_pow_n_plus_1 (n : ℕ) : 2 ≤ 2 ^ (n + 1)

theorem get_drop_eq_drop_get_comp_cast {α : Type*} {m : ℕ} (l : List α) (h : m ≤ l.length) :
    (l.drop m).get = drop m h l.get ∘ Fin.cast (List.length_drop)

omit [Finite F] in
lemma D_def : evalDomain D x 0 = x • D

lemma linsolve_to_BerlekampWelch_condition {e k : ℕ}
  [NeZero n]
  {ωs f : Fin n → F}
  {v : Fin (2 * e + k) → F}
  (h_sol : linsolve (BerlekampWelchMatrix e k ωs f) (Rhs e ωs f) = some v)
  : BerlekampWelchCondition e k ωs f (solutionToE e k v) (solutionToQ e k v)

@[simp]
theorem eval_poly_at_root (k : ℕ) : (Z (k+1))^2 + (Z (k+1)) * Z k + 1 = 0

theorem insertNth_zero_eq_cases {n : ℕ} {α : Fin (n + 1) → Sort u} :
    insertNth 0 = cases (motive := α)

theorem matchSize_eq_iff_forall_eq (l₁ l₂ : List α) (unit : α) :
    (fun (x, y) => x = y) (matchSize l₁ l₂ unit) ↔ ∀ i : Nat, l₁.getD i unit = l₂.getD i unit

@[simp]
theorem Set.not_mem_language_iff {α β} (rel : Set (α × β)) (stmt : α) :
    stmt ∉ rel.language ↔ ∀ wit, (stmt, wit) ∉ rel

lemma eval₂_f_eq_C (r : R) (x : P) : eval₂ (P := P) (C : R →+* P) x (C r) = C r

@[simp] theorem rightpad_getD_eq_getD (l : List α) (n : Nat) (unit : α) (i : Nat) :
    (rightpad n unit l).getD i unit = l.getD i unit

theorem init_dconcat {motive : Fin (n + 1) → Sort u} (v : (i : Fin n) → motive (castSucc i))
    (a : motive (last n)) : (fun i => (v :+ᵈ⟨motive⟩ a) (castSucc i)) = v

@[simp] lemma extract_dir : pSpec⟦start:stop⟧.dir = pSpec.dir⟦start:stop⟧

theorem sum_le_of_divSum?_eq_some {m : ℕ} {n : Fin m → ℕ} {k : Fin (∑ j, n j)} {i : Fin m}
    (hi : divSum? n k = some i) : ∑ j : Fin i, n (castLE i.isLt.le j) ≤ k

@[simp]
theorem dcons_succ {motive : Fin (n + 1) → Sort u} (a : motive 0)
    (v : (i : Fin n) → motive i.succ) (i : Fin n) : (a ::ᵈ⟨motive⟩ v) i.succ = v i

@[simp, grind] lemma C_pos : 0 < sz.C

@[simp]
theorem bool_accepts_iff : (bool j).accepts x ↔ x j * (x j - 1) = 0

@[grind =] theorem idxOf'_cons [BEq α] {a : α} {x : α} {xs : List α} :
    idxOf' a (x :: xs) = bif x == a then 0 else idxOf' a xs + 1

theorem add_comm (m n : ChurchNat α) : add m n = add n m

@[local grind _=_]
private lemma support_eq_support_toFinsupp {f : F[X][Y]} : f.support = f.toFinsupp.support

lemma towerRingHomForwardMap_join {k : ℕ} (h_pos : k > 0) (hi lo : ConcreteBTField (k - 1)) :
  towerRingHomForwardMap (k:=k) (《 hi, lo 》) =
    BinaryTower.join_via_add_smul (k:=k) (h_pos:=by omega)
      (hi_btf := towerRingHomForwardMap (k:=k-1) hi)
      (lo_btf := towerRingHomForwardMap (k:=k-1) lo)

theorem getBit_repr {ℓ : Nat} : ∀ j, j < 2^ℓ →
  j = ∑ k ∈ Finset.Icc 0 (ℓ-1), (getBit k j) * 2^k

theorem funext₂_iff {α : Sort u} {β : α → Sort v} {γ : (a : α) → β a → Sort w}
    {f g : (a : α) → (b : β a) → γ a b} : f = g ↔ ∀ a b, f a b = g a b

lemma extract_start_zero_eq_take {n : ℕ} {α : Fin n → Sort*} (stop : ℕ) (h : stop ≤ n)
    (v : (i : Fin n) → α i) : extract 0 stop (Nat.zero_le _) h v = take stop h v

lemma evenize_eval {f : Polynomial F} {s : F} :
    (evenize f).eval s = f.eval (s * s)

@[simp]
theorem vconcat_castSucc (v : Fin n → α) (a : α) (i : Fin n) :
    vconcat v a (castSucc i) = v i

lemma weight_ξ_bound (x₀ : F) {D : ℕ} (hD : D ≥ Bivariate.totalDegree H) :
  weight_Λ_over_𝒪 (ξ x₀ R H) D ≤
    WithBot.some ((Bivariate.natDegreeY R - 1) * (D - Bivariate.natDegreeY H + 1))

@[simp]
theorem fflatten₂_splitSum {A : Sort u} {B : Sort v} {F : A → B → Sort w} {m : ℕ} {n : Fin m → ℕ}
    {α : (i : Fin m) → (j : Fin (n i)) → A}
    {β : (i : Fin m) → (j : Fin (n i)) → B}
    (v : (k : Fin (vsum n)) → F (vflatten α k) (vflatten β k)) (k : Fin (vsum n)) :
    fflatten₂ (fun i j => v (embedSum i j)) k = cast (by simp) (v k)

@[simp]
theorem removeNth_update : removeNth p (update s p y) = removeNth p s

theorem knowledgeSoundness_implies_soundness (relIn : Set (StmtIn × WitIn))
    (relOut : Set (StmtOut × WitOut))
    (verifier : Verifier oSpec StmtIn StmtOut pSpec)
    (knowledgeError : ℝ≥0) (hLt : knowledgeError < 1) :
      knowledgeSoundness init impl relIn relOut verifier knowledgeError →
        soundness init impl relIn.language relOut.language verifier knowledgeError

@[grind]
lemma degreeX_le_degreeX_sub_degreeX [IsDomain F] {f q : F[X][Y]} (hf : f ≠ 0) (hg : q * f ≠ 0) :
  degreeX q ≤ degreeX (q * f) - degreeX f
</all_available_lemmas>

<local_ctx>
import Init.Data.List.FinRange

import Mathlib.Algebra.Field.Basic

import Mathlib.Algebra.Polynomial.Basic

import Mathlib.Algebra.Polynomial.Degree.Definitions

import Mathlib.Algebra.Polynomial.FieldDivision

import Mathlib.Data.Finset.Insert

import Mathlib.Data.Fintype.Card

import Mathlib.Data.Matrix.Mul

import Mathlib.Data.Matrix.Reflection

import ArkLib.Data.CodingTheory.Basic

import ArkLib.Data.Polynomial.Interface

import ArkLib.Data.CodingTheory.BerlekampWelch.ElocPoly

import ArkLib.Data.CodingTheory.BerlekampWelch.Sorries

namespace BerlekampWelch

variable {α : Type} {F : Type} [Field F]
         {n e k : ℕ}
         {i : Fin n}
         {j : Fin (2 * e + k)}
         {ωs f : Fin n → F}
         {v : Fin (2 * e + k) → F}
         {E Q : Polynomial F}
         {p : Polynomial F}

section

open Polynomial Finset in

open Fin

open Polynomial

variable [DecidableEq F]

def solutionToQ (e k : ℕ) (v : Fin (2 * e + k) → F) : Polynomial F :=
  ⟨
    (Finset.range (e + k)).filter (fun x => liftF v (e + x) ≠ 0),
    fun i => if i < e + k then liftF v (e + i) else 0,
    by admit /- proof elided -/
  ⟩
</local_ctx>

<target_theorem>
@[simp]
lemma solutionToQ_zero {v : Fin (2 * 0 + 0) → F} :
  solutionToQ (F := F) 0 0 v = 0 :=
</target_theorem>

