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:
* <used_lib_defs>...</used_lib_defs>: Imported library definitions directly used by the theorem.
* <used_repo_defs>...</used_repo_defs>: Definitions from the local project (but outside the current file), directly or transitively used by the theorem.
* <lib_lemmas>...</lib_lemmas>: Imported library lemmas/theorems that may assist the proof.
* <repo_lemmas>...</repo_lemmas>: Lemmas/theorems defined in the local project outside this file.
* <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 used definitions and helpful lemmas (used_lib_defs, used_repo_defs, lib_lemmas, repo_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:
<used_lib_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)
</used_lib_defs>

<repo_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]
</repo_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:
<used_lib_defs>
ZMod in Mathlib.Data.ZMod.Defs
Vector in Init.Data.Vector.Basic
One in Init.Prelude
Zero in Init.Prelude
Fin in Init.Prelude
String in Init.Prelude
Unit in Init.Prelude
List in Init.Prelude
Field in Mathlib.Algebra.Field.Defs
Inhabited in Init.Prelude
Vector.mapM in Init.Data.Vector.Basic
id in Init.Prelude
Nat in Init.Prelude
cast in Init.Prelude
Fact in Mathlib.Logic.Basic
Vector.cast in Init.Data.Vector.Basic
Vector.foldl in Init.Data.Vector.Basic
Vector.map in Init.Data.Vector.Basic
Array in Init.Prelude
List.foldl in Init.Prelude
</used_lib_defs>

<used_repo_defs>
syntax "infer_constant_length" : tactic

syntax "let " ident " <== " term : doElem

syntax "let " ident " : " term " <== " term : doElem

macro_rules
  | `(doElem| let $x <== $e) => `(doElem| let $x ← HasAssignEq.assignEq $e)
  | `(doElem| let $x : $t <== $e) => `(doElem| let $x : $t ← HasAssignEq.assignEq $e)

macro_rules
  | `(tactic|infer_constant_length) => `(tactic|(
    apply ConstantLength.fromConstantLength
    try simp only [circuit_norm]
    try intros
    try ac_rfl))

example :
  let add (x : Expression F) := do
    let y : Expression F ← witness fun _ => 1
    let z ← witness fun eval => eval (x + y)
    assertZero (x + y - z)
    pure z
  ConstantLength add := by admit /- proof elided -/

def F p := ZMod p

@[reducible]
def fields (n : ℕ) := fun F => Vector F n

def IsBool {α : Type*} [Zero α] [One α] (x : α) : Prop := x = 0 ∨ x = 1

def map {m : ℕ} (xs : Vector α m) (body : α → Circuit F β)
    (_constant : ConstantLength body := by admit /- proof elided -/
    ) : Circuit F (Vector β m) :=
  xs.mapM body

def Circuit (F : Type) [Field F] (α : Type) := ℕ → α × List (Operation F)

inductive Operation (F : Type) [Field F] where
  | witness : (m : ℕ) → (compute : Environment F → Vector F m) → Operation F
  | assert : Expression F → Operation F
  | lookup : Lookup F → Operation F
  | subcircuit : {n : ℕ} → Subcircuit F n → Operation F

structure Condition (F : Type) [Field F] where
  witness (offset : ℕ) : (m : ℕ) → (Environment F → Vector F m) → Prop := fun _ _ => True
  assert (offset : ℕ) (_ : Expression F) : Prop := True
  lookup (offset : ℕ) (_ : Lookup F) : Prop := True
  subcircuit (offset : ℕ) {m : ℕ} (_ : Subcircuit F m) : Prop := True

inductive FlatOperation (F : Type) where
  | witness : (m : ℕ) → (Environment F → Vector F m) → FlatOperation F
  | assert : Expression F → FlatOperation F
  | lookup : Lookup F → FlatOperation F

structure Subcircuit (F : Type) [Field F] (offset : ℕ) where
  ops : List (FlatOperation F)

  
  
  
  Soundness : Environment F → Prop
  Completeness : Environment F → Prop
  UsesLocalWitnesses : Environment F → Prop

  
  
  localLength : ℕ

  
  imply_soundness : ∀ env,
    ConstraintsHoldFlat env ops → Soundness env

  
  implied_by_completeness : ∀ env, env.ExtendsVector (localWitnesses env ops) offset →
    Completeness env → ConstraintsHoldFlat env ops

  
  imply_usesLocalWitnesses : ∀ env, env.ExtendsVector (localWitnesses env ops) offset →
    UsesLocalWitnesses env

  
  localLength_eq : localLength = FlatOperation.localLength ops

@[circuit_norm]
def localWitnesses (env : Environment F) : (l : List (FlatOperation F)) → Vector F (localLength l)
  | [] => #v[]
  | witness _ compute :: ops => compute env ++ localWitnesses env ops
  | assert _ :: ops | lookup _ :: ops => localWitnesses env ops

@[circuit_norm]
def lookup {Row : TypeMap} [ProvableType Row] (table : Table F Row)  (entry : Row (Expression F)) : Circuit F Unit := fun _ =>
  ((), [.lookup { table := table.toRaw, entry := toElements entry }])

@[circuit_norm]
def Table.toRaw (table : Table F Row) : RawTable F where
  name := table.name
  arity := size Row
  Contains row := table.Contains (fromElements row)
  Soundness row := table.Soundness (fromElements row)
  Completeness row := table.Completeness (fromElements row)
  imply_soundness row := table.imply_soundness (fromElements row)
  implied_by_completeness row := table.implied_by_completeness (fromElements row)

structure RawTable (F : Type) where
  name : String
  arity : ℕ
  Contains : Vector F arity → Prop
  Soundness : Vector F arity → Prop
  Completeness : Vector F arity → Prop
  imply_soundness : ∀ row, Contains row → Soundness row
  implied_by_completeness : ∀ row, Completeness row → Contains row

structure StaticTable (F : Type) (Row : TypeMap) [ProvableType Row] where
  name : String
  length : ℕ
  row : Fin length → Row F
  
  
  
  index : Row F → ℕ
  Spec : Row F → Prop
  contains_iff : ∀ t, (∃ i, t = row i) ↔ Spec t

def Contains (table : StaticTable F Row) (row : Row F) :=
  ∃ i : Fin table.length, row = table.row i

instance ProvableType.fromStruct {α : TypeMap} [ProvableStruct α] : ProvableType α where
  size := combinedSize α
  toElements x :=
    toComponents x |> componentsToElements (components α) |>.cast combinedSize_eq.symm
  fromElements v :=
    v.cast combinedSize_eq |> componentsFromElements (components α) |> fromComponents
  fromElements_toElements x := by admit /- proof elided -/

@[reducible]
def TypeMap := Type → Type

structure Table (F : Type) (Row : TypeMap) [ProvableType Row] where
  name : String
   
  Contains : Row F → Prop

   
  Soundness : Row F → Prop
  Completeness : Row F → Prop

  imply_soundness : ∀ row, Contains row → Soundness row
  implied_by_completeness : ∀ row, Completeness row → Contains row

inductive Expression (F : Type) where
  | var : Variable F -> Expression F
  | const : F -> Expression F
  | add : Expression F -> Expression F -> Expression F
  | mul : Expression F -> Expression F -> Expression F

structure Variable (F : Type) where
  index : ℕ

def const (x : α F) : Var α F :=
  let values : Vector F _ := toElements x
  fromVars (values.map .const)

@[reducible] def Var (M : TypeMap) (F : Type) := M (Expression F)

@[circuit_norm]
def fromVars (vars : Vector (Expression F) (size M)) := fromElements vars

structure Lookup (F : Type) where
  table : RawTable F
  entry : Vector (Expression F) table.arity

class Witnessable (F : Type) [Field F] (value : outParam TypeMap) (var : TypeMap) [ProvableType value] where
  witness : ((Environment F) → value F) → Circuit F (var F)
  var_eq : var F = value (Expression F) := by admit /- proof elided -/

structure Environment (F : Type) where
  get : ℕ → F

@[circuit_norm]
def localLength : List (FlatOperation F) → ℕ
  | [] => 0
  | witness m _ :: ops => m + localLength ops
  | assert _ :: ops | lookup _ :: ops => localLength ops

def ConstraintsHoldFlat (eval : Environment F) : List (FlatOperation F) → Prop
  | [] => True
  | op :: ops => match op with
    | assert e => (eval e = 0) ∧ ConstraintsHoldFlat eval ops
    | lookup { table, entry } =>
      table.Contains (entry.map eval) ∧ ConstraintsHoldFlat eval ops
    | _ => ConstraintsHoldFlat eval ops

class ConstantLength (circuit : α → Circuit F β) where
  localLength : ℕ
  localLength_eq : ∀ (a : α) (n : ℕ), (circuit a).localLength n = localLength

def ConstantLength.fromConstantLength {circuit : α → Circuit F β} [Inhabited α]
    (h : ∀ (a : α) n, (circuit a).localLength n = (circuit default).localLength 0) : ConstantLength circuit where
  localLength := (circuit default).localLength 0
  localLength_eq a n := h a n

class HasAssignEq (β : Type) (F : outParam Type) [Field F] where
  assignEq : β → Circuit F β

structure FormalCircuit (F : Type) [Field F] (Input Output : TypeMap) [ProvableType Input] [ProvableType Output]
    extends elaborated : ElaboratedCircuit F Input Output where
  Assumptions (_ : Input F) : Prop := True
  Spec : Input F → Output F → Prop
  soundness : Soundness F elaborated Assumptions Spec
  completeness : Completeness F elaborated Assumptions

class ElaboratedCircuit (F : Type) (Input Output : TypeMap) [Field F] [ProvableType Input] [ProvableType Output] where
  main : Var Input F → Circuit F (Var Output F)

   
  localLength : Var Input F → ℕ

   
  localLength_eq : ∀ input offset, (main input).localLength offset = localLength input
    := by admit /- proof elided -/

structure GeneralFormalCircuit (F : Type) (Input Output : TypeMap) [Field F] [ProvableType Input] [ProvableType Output]
    extends elaborated : ElaboratedCircuit F Input Output where
  Assumptions : Input F → Prop 
  Spec : Input F → Output F → Prop 
  soundness : GeneralFormalCircuit.Soundness F elaborated Spec
  completeness : GeneralFormalCircuit.Completeness F elaborated Assumptions

@[circuit_norm]
def Soundness (F : Type) [Field F] (circuit : ElaboratedCircuit F Input Output)
    (Assumptions : Input F → Prop) (Spec : Input F → Output F → Prop) :=
  
  ∀ offset : ℕ, ∀ env,
  
  ∀ input_var : Var Input F, ∀ input : Input F, eval env input_var = input →
  Assumptions input →
  
  ConstraintsHold.Soundness env (circuit.main input_var |>.operations offset) →
  
  let output := eval env (circuit.output input_var offset)
  Spec input output

@[reducible, circuit_norm]
def operations (circuit : Circuit F α) (offset : ℕ) : Operations F :=
  (circuit offset).2

@[reducible, circuit_norm]
def Operations (F : Type) [Field F] := List (Operation F)

@[reducible, circuit_norm]
def output (circuit : Circuit F α) (offset : ℕ) : α :=
  (circuit offset).1

@[circuit_norm]
def ConstraintsHold.Soundness (eval : Environment F) : List (Operation F) → Prop
  | [] => True
  | .witness _ _ :: ops => ConstraintsHold.Soundness eval ops
  | .assert e :: ops => eval e = 0 ∧ ConstraintsHold.Soundness eval ops
  | .lookup { table, entry } :: ops =>
    table.Soundness (entry.map eval) ∧ ConstraintsHold.Soundness eval ops
  | .subcircuit s :: ops =>
    s.Soundness eval ∧ ConstraintsHold.Soundness eval ops

@[circuit_norm]
def GeneralFormalCircuit.Soundness (F : Type) [Field F] (circuit : ElaboratedCircuit F Input Output) (Spec : Input F → Output F → Prop) :=
  
  ∀ offset : ℕ, ∀ env,
  
  ∀ input_var : Var Input F, ∀ input : Input F, eval env input_var = input →
  
  ConstraintsHold.Soundness env (circuit.main input_var |>.operations offset) →
  
  let output := eval env (circuit.output input_var offset)
  Spec input output

@[explicit_provable_type]
def eval (env : Environment F) (x : Var α F) : α F :=
  let vars := toVars x
  let values := vars.map (Expression.eval env)
  fromElements values

@[circuit_norm]
def toVars (var : M (Expression F)) := toElements var

@[circuit_norm]
def eval (env : Environment F) : Expression F → F
  | var v => env.get v.index
  | const c => c
  | add x y => eval env x + eval env y
  | mul x y => eval env x * eval env y

@[circuit_norm]
def FormalAssertion.Soundness (F : Type) [Field F] (circuit : ElaboratedCircuit F Input unit)
    (Assumptions : Input F → Prop) (Spec : Input F → Prop) :=
  
  ∀ offset : ℕ, ∀ env,
  
  ∀ input_var : Var Input F, ∀ input : Input F, eval env input_var = input →
  Assumptions input →
  
  ConstraintsHold.Soundness env (circuit.main input_var |>.operations offset) →
  
  Spec input

@[reducible]
def unit (_ : Type) := Unit

@[circuit_norm]
def subcircuit (circuit : FormalCircuit F β α) (b : Var β F) : Circuit F (Var α F) :=
  fun offset =>
    let a := circuit.output b offset
    let subcircuit := circuit.toSubcircuit offset b
    (a, [.subcircuit subcircuit])

def FormalAssertion.toSubcircuit (circuit : FormalAssertion F β)
    (n : ℕ) (input_var : Var β F) : Subcircuit F n :=
  let ops := circuit.main input_var |>.operations n
  have h_consistent : ops.SubcircuitsConsistent n := circuit.subcircuitsConsistent input_var n

  {
    ops := ops.toFlat,
    Soundness env := circuit.Assumptions (eval env input_var) → circuit.Spec (eval env input_var),
    Completeness env := circuit.Assumptions (eval env input_var) ∧ circuit.Spec (eval env input_var),
    UsesLocalWitnesses _ := True,
    localLength := circuit.localLength input_var

    imply_soundness := by admit /- proof elided -/

@[circuit_norm]
def localLength : Operation F → ℕ
  | .witness m _ => m
  | .assert _ => 0
  | .lookup _ => 0
  | .subcircuit s => s.localLength

@[circuit_norm]
def localLength : Operations F → ℕ
  | [] => 0
  | .witness m _ :: ops => m + localLength ops
  | .assert _ :: ops => localLength ops
  | .lookup _ :: ops => localLength ops
  | .subcircuit s :: ops => s.localLength + localLength ops

structure FormalAssertion (F : Type) (Input : TypeMap) [Field F] [ProvableType Input]
    extends elaborated : ElaboratedCircuit F Input unit where
  Assumptions : Input F → Prop
  Spec : Input F → Prop
  soundness : FormalAssertion.Soundness F elaborated Assumptions Spec
  completeness : FormalAssertion.Completeness F elaborated Assumptions Spec

  
  localLength _ := 0
  
  output _ _ := ()

@[circuit_norm]
def SubcircuitsConsistent (offset : ℕ) (ops : Operations F) := ops.forAll offset {
  subcircuit offset {n} _ := n = offset
}

 @[circuit_norm]
def forAll (offset : ℕ) (condition : Condition F) : Operations F → Prop
  | [] => True
  | .witness m c :: ops => condition.witness offset m c ∧ forAll (m + offset) condition ops
  | .assert e :: ops => condition.assert offset e ∧ forAll offset condition ops
  | .lookup l :: ops => condition.lookup offset l ∧ forAll offset condition ops
  | .subcircuit s :: ops => condition.subcircuit offset s ∧ forAll (s.localLength + offset) condition ops

def FlatOperation.forAll (offset : ℕ) (condition : Condition F) : List (FlatOperation F) → Prop
  | [] => True
  | .witness m c :: ops => condition.witness offset m c ∧ forAll (m + offset) condition ops
  | .assert e :: ops => condition.assert offset e ∧ forAll offset condition ops
  | .lookup l :: ops => condition.lookup offset l ∧ forAll offset condition ops

@[reducible, circuit_norm]
def localLength (circuit : Circuit F α) (offset := 0) : ℕ :=
  Operations.localLength (circuit offset).2

@[circuit_norm]
def FormalAssertion.Completeness (F : Type) [Field F] (circuit : ElaboratedCircuit F Input unit)
    (Assumptions : Input F → Prop) (Spec : Input F → Prop) :=
  
  ∀ offset, ∀ env, ∀ input_var : Var Input F,
  env.UsesLocalWitnessesCompleteness offset (circuit.main input_var |>.operations offset) →
  
  ∀ input : Input F, eval env input_var = input →
  Assumptions input → Spec input →
  
  ConstraintsHold.Completeness env (circuit.main input_var |>.operations offset)

@[circuit_norm]
def ConstraintsHold.Completeness (eval : Environment F) : List (Operation F) → Prop
  | [] => True
  | .witness _ _ :: ops => ConstraintsHold.Completeness eval ops
  | .assert e :: ops => eval e = 0 ∧ ConstraintsHold.Completeness eval ops
  | .lookup { table, entry } :: ops =>
    table.Completeness (entry.map eval) ∧ ConstraintsHold.Completeness eval ops
  | .subcircuit s :: ops =>
    s.Completeness eval ∧ ConstraintsHold.Completeness eval ops

@[circuit_norm]
def Completeness (F : Type) [Field F] (circuit : ElaboratedCircuit F Input Output)
    (Assumptions : Input F → Prop) :=
  
  ∀ offset : ℕ, ∀ env, ∀ input_var : Var Input F,
  env.UsesLocalWitnessesCompleteness offset (circuit.main input_var |>.operations offset) →
  
  ∀ input : Input F, eval env input_var = input →
  Assumptions input →
  
  ConstraintsHold.Completeness env (circuit.main input_var |>.operations offset)

@[circuit_norm]
def GeneralFormalCircuit.Completeness (F : Type) [Field F] (circuit : ElaboratedCircuit F Input Output) (Assumptions : Input F → Prop) :=
  
  ∀ offset : ℕ, ∀ env, ∀ input_var : Var Input F,
  env.UsesLocalWitnessesCompleteness offset (circuit.main input_var |>.operations offset) →
  
  ∀ input : Input F, eval env input_var = input →
  Assumptions input →
  
  ConstraintsHold.Completeness env (circuit.main input_var |>.operations offset)

def toFlat : Operations F → List (FlatOperation F)
  | [] => []
  | .witness m c :: ops => .witness m c :: toFlat ops
  | .assert e :: ops => .assert e :: toFlat ops
  | .lookup l :: ops => .lookup l :: toFlat ops
  | .subcircuit s :: ops => s.ops ++ toFlat ops

def Environment.UsesLocalWitnesses (env : Environment F) (offset : ℕ) (ops : Operations F) : Prop :=
  ops.forAllFlat offset { witness n _ compute := env.ExtendsVector (compute env) n }

@[circuit_norm]
def Environment.ExtendsVector (env : Environment F) (wit : Vector F n) (offset : ℕ) : Prop :=
  ∀ i : Fin n, env.get (offset + i.val) = wit[i.val]

def Operations.forAllFlat (n : ℕ) (condition : Condition F) (ops : Operations F) : Prop :=
  forAll n { condition with subcircuit n _ s := FlatOperation.forAll n condition s.ops } ops

def GeneralFormalCircuit.toSubcircuit (circuit : GeneralFormalCircuit F β α)
    (n : ℕ) (input_var : Var β F) : Subcircuit F n :=
  let ops := circuit.main input_var |>.operations n
  have h_consistent : ops.SubcircuitsConsistent n := circuit.subcircuitsConsistent input_var n

  have imply_soundness : ∀ env : Environment F,
      let input := eval env input_var
      let output := eval env (circuit.output input_var n)
      ConstraintsHoldFlat env ops.toFlat → circuit.Spec input output :=

def FormalCircuit.toSubcircuit (circuit : FormalCircuit F β α)
    (n : ℕ) (input_var : Var β F) : Subcircuit F n :=
  let ops := circuit.main input_var |>.operations n
  have h_consistent : ops.SubcircuitsConsistent n := circuit.subcircuitsConsistent input_var n

  have imply_soundness : ∀ env : Environment F,
    let input := eval env input_var
    let output := eval env (circuit.output input_var n)
    ConstraintsHoldFlat env ops.toFlat → circuit.Assumptions input → circuit.Spec input output :=

@[reducible]
def fieldPair : TypeMap := fun F => F × F

@[reducible] def field : TypeMap := id

@[circuit_norm]
def ConstraintsHold (eval : Environment F) : List (Operation F) → Prop
  | [] => True
  | .witness _ _ :: ops => ConstraintsHold eval ops
  | .assert e :: ops => eval e = 0 ∧ ConstraintsHold eval ops
  | .lookup { table, entry, .. } :: ops =>
    table.Contains (entry.map eval) ∧ ConstraintsHold eval ops
  | .subcircuit s :: ops =>
    ConstraintsHoldFlat eval s.ops ∧ ConstraintsHold eval ops

def toList : Operations F → List (Operation F) := id

def induct {motive : Operations F → Sort*}
  (empty : motive [])
  (witness : ∀ m c ops, motive ops → motive (.witness m c :: ops))
  (assert : ∀ e ops, motive ops → motive (.assert e :: ops))
  (lookup : ∀ l ops, motive ops → motive (.lookup l :: ops))
  (subcircuit : ∀ {n} (s : Subcircuit F n) ops, motive ops → motive (.subcircuit s :: ops))
    (ops : Operations F) : motive ops :=
  match ops with
  | [] => empty
  | .witness m c :: ops => witness m c ops (induct empty witness assert lookup subcircuit ops)
  | .assert e :: ops => assert e ops (induct empty witness assert lookup subcircuit ops)
  | .lookup l :: ops => lookup l ops (induct empty witness assert lookup subcircuit ops)
  | .subcircuit s :: ops => subcircuit s ops (induct empty witness assert lookup subcircuit ops)

@[reducible, circuit_norm]
def forAll (circuit : Circuit F α) (n : ℕ) (prop : Condition F) :=
  (circuit.operations n).forAll n prop
</used_repo_defs>

<lib_lemmas>
Array.foldl_toList in Init.Data.Array.Bootstrap
List.foldl_cons in Init.Data.List.Basic
List.foldl_nil in Init.Data.List.Basic
Vector.foldl_mk in Init.Data.Vector.Lemmas
Vector.getElem_map in Init.Data.Vector.Lemmas
Vector.toList_toArray in Init.Data.Vector.Lemmas
ZMod.val_one in Mathlib.Data.ZMod.Basic
Vector.foldl_append in Init.Data.Vector.Lemmas
Nat.add_sub_self_left in Init.Data.Nat.Basic
Nat.min_add_right_self in Init.Data.Nat.Lemmas
Nat.min_def in Init.Data.Nat.Basic
Nat.strong_induction_on in Mathlib.Data.Nat.Init
Vector.cast_cast in Init.Data.Vector.Lemmas
Vector.getElem_cast in Init.Data.Vector.Lemmas
Vector.getElem_drop in Init.Data.Vector.Lemmas
Vector.getElem_take in Init.Data.Vector.Lemmas
Vector.map_append in Init.Data.Vector.Lemmas
</lib_lemmas>

<repo_lemmas>
theorem toList_length_one {α : Type} (v : Vector α 1) :
    v.toList = [v[0]]

theorem one_land_of_IsBool (a : ℕ) (h : IsBool a) : 1 &&& a = a

theorem land_one_of_IsBool (a : ℕ) (h : IsBool a) : a &&& 1 = a

@[circuit_norm]
theorem pure_def {α} (a : α) : (pure a : Circuit F α) = fun _ => (a, [])

theorem val_of_IsBool {p : ℕ} [Fact p.Prime] {x : F p} (h : IsBool x) : IsBool x.val

@[circuit_norm]
theorem one {α : Type*} [Zero α] [One α] : IsBool (1 : α)

@[circuit_norm]
theorem zero {α : Type*} [Zero α] [One α] : IsBool (0 : α)

@[circuit_norm ↓]
theorem eval_fieldPair {F : Type} [Field F] (env : Environment F) (t : Var fieldPair F) :
  ProvableType.eval env t = (match t with | (x, y) => (Expression.eval env x, Expression.eval env y))

theorem toList_length_two {α : Type} (v : Vector α 2) :
    v.toList = [v[0], v[1]]

theorem List.foldl_and_IsBool (l : List ℕ) :
    IsBool (List.foldl (· &&& ·) 1 l : ℕ)

theorem List.and_foldl_eq_foldl (a : ℕ) (orig : ℕ) (l : List ℕ) :
    a &&& List.foldl (· &&& ·) orig l = List.foldl (· &&& ·) (a &&& orig) l

@[circuit_norm ↓]
theorem eval_fields {F : Type} [Field F] (env : Environment F) (x : Var (fields n) F) :
  ProvableType.eval env x = x.map (Expression.eval env)

theorem append_take_drop {v : Vector α (n + m)} :
    (v.take n |>.cast Nat.min_add_right_self) ++ (v.drop n |>.cast (Nat.add_sub_self_left n m)) = v

@[ext]
theorem ext {f g : Circuit F α}
  (h_output : ∀ n, f.output n = g.output n)
  (h_operations : ∀ n, f.operations n = g.operations n) :
    f = g

theorem ext_iff {f g : Circuit F α} :
  (f = g) ↔ (∀ n, (f.output n = g.output n) ∧ (f.operations n = g.operations n))

@[circuit_norm] theorem ConstraintsHold.bind_soundness {f : Circuit F α} {g : α → Circuit F β} (n : ℕ) :
  ConstraintsHold.Soundness env ((f >>= g).operations n)
  ↔ ConstraintsHold.Soundness env (f.operations n) ∧
    ConstraintsHold.Soundness env ((g (f.output n)).operations (n + f.localLength n))

@[circuit_norm]
theorem bind_forAll {f : Circuit F α} {g : α → Circuit F β} :
  ((f >>= g).operations n).forAll n prop ↔
    (f.operations n).forAll n prop ∧ (((g (f.output n)).operations (n + f.localLength n)).forAll (n + f.localLength n)) prop

@[circuit_norm]
theorem forAll_append {condition : Condition F} {offset : ℕ} {as bs: Operations F} :
  forAll offset condition (as ++ bs) ↔
    forAll offset condition as ∧ forAll (as.localLength + offset) condition bs

@[circuit_norm]
theorem forAll_empty {condition : Condition F} {n : ℕ} : forAll n condition [] = True

theorem ConstraintsHold.soundness_iff_forAll (n : ℕ) (env : Environment F) (ops : Operations F) :
  ConstraintsHold.Soundness env ops ↔ ops.forAll n {
    assert _ e := env e = 0,
    lookup _ l := l.table.Soundness (l.entry.map env),
    subcircuit _ _ s := s.Soundness env
  }
</repo_lemmas>

<local_ctx>
import Clean.Circuit

import Clean.Utils.Field

import Clean.Gadgets.Boolean

import Clean.Utils.Bitwise

import Clean.Utils.Vector

import Clean.Utils.BinaryOps

import Clean.Circuit.Theorems

import Mathlib.Data.Nat.Bitwise

open IsBool

namespace Circomlib

variable {p : ℕ} [Fact p.Prime]

open Circuit (bind_output_eq bind_localLength_eq bind_forAll)

open Operations (append_localLength)

open BinaryOps (List.foldl_and_IsBool List.and_foldl_eq_foldl)

namespace XOR

end XOR

namespace AND

def main (input : Expression (F p) × Expression (F p)) := do
  let a := input.1
  let b := input.2
  let out <== a*b
  return out

end AND

namespace OR

end OR

namespace NOT

end NOT

namespace NAND

end NAND

namespace NOR

end NOR

namespace MultiAND

def main : {n : ℕ} → Vector (Expression (F p)) n → Circuit (F p) (Expression (F p))
  | 0, _ =>
    return (1 : F p)
  | 1, input =>
    return input[0]
  | 2, input =>
    AND.circuit.main (input[0], input[1])
  | n + 3, input => do
    let n1 := (n + 3) / 2
    let n2 := (n + 3) - n1

    let input1 : Vector (Expression (F p)) n1 := input.take n1 |>.cast (by admit /- proof elided -/
    )
    let input2 : Vector (Expression (F p)) n2 := input.drop n1 |>.cast (by admit /- proof elided -/
    )

    let out1 ← main input1
    let out2 ← main input2

    AND.circuit.main (out1, out2)

def Assumptions (n : ℕ) (input : fields n (F p)) : Prop :=
  ∀ (i : ℕ) (h : i < n), IsBool input[i]

def Spec (n : ℕ) (input : fields n (F p)) (output : F p) : Prop :=
  output.val = (input.map (·.val)).foldl (· &&& ·) 1 ∧ IsBool output
</local_ctx>

<target_theorem>
theorem soundness {p : ℕ} [Fact p.Prime] (n : ℕ) :
    ∀ (offset : ℕ) (env : Environment (F p)) (input_var : Var (fields n) (F p))
      (input : fields n (F p)),
    input = eval env input_var →
    Assumptions n input →
    Circuit.ConstraintsHold.Soundness env ((main input_var).operations offset) →
    Spec n input (env ((main input_var).output offset)) :=
</target_theorem>

