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Project-declaredLean 4.31.0 · mathlib@fabf563a7c95

Eval Consistency of rel Out star

ArkLib.Lattices.Ajtai.InnerOuter.evalConsistency_of_relOut_star

Project documentation

Eval-consistency of the extracted opening (Hachi Lemma 8, case (C), part 2 , Eq. (15)): the shared-ŵ c3 row plus the coordinate-isolated, unit-divided c4 rows discharge the w/c3/c4 hypotheses of evalConsistency_of_star at the shared recomposed carrier w := G_{2^r} *ᵥ ŵ.

Exact Lean statement

theorem evalConsistency_of_relOut_star (hq5 : q % 8 = 5) {b ω γ : ℕ} (hκ : (2 * ω) ^ 2 < q)
    (stmt : QuadEvalStatement 𝓜(q, α) innerRows (2 ^ m) messageDigits outerRows (2 ^ r) innerDigits
      dRows)
    (v : CarrierCom 𝓜(q, α) dRows)
    (fam : Fin (2 ^ r + 1) → (Fin (2 ^ r) → ShortChallenge 𝓜(q, α) ω))
    (resp : Fin (2 ^ r + 1) →
      QuadEvalResponse 𝓜(q, α) innerRows (2 ^ m) messageDigits (2 ^ r) innerDigits zDigits)
    (hrel : ∀ j, ((stmt, v, fam j), resp j) ∈ relOut 𝓜(q, α) (b : ZMod q) ω γ)
    (hstar : ∃ e, StarAt fam e)
    (hw : ∀ j, (resp j).carrierDec = (resp (central fam)).carrierDec) :
    evalConsistency 𝓜(q, α) (b : ZMod q) stmt.avec stmt.bvec stmt.y
      (extractedOpening 𝓜(q, α) (b : ZMod q) fam resp)

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem evalConsistency_of_relOut_star (hq5 : q % 8 = 5) {b ω γ : } (hκ : (2 * ω) ^ 2 < q)    (stmt : QuadEvalStatement 𝓜(q, α) innerRows (2 ^ m) messageDigits outerRows (2 ^ r) innerDigits      dRows)    (v : CarrierCom 𝓜(q, α) dRows)    (fam : Fin (2 ^ r + 1)  (Fin (2 ^ r)  ShortChallenge 𝓜(q, α) ω))    (resp : Fin (2 ^ r + 1)       QuadEvalResponse 𝓜(q, α) innerRows (2 ^ m) messageDigits (2 ^ r) innerDigits zDigits)    (hrel :  j, ((stmt, v, fam j), resp j)  relOut 𝓜(q, α) (b : ZMod q) ω γ)    (hstar :  e, StarAt fam e)    (hw :  j, (resp j).carrierDec = (resp (central fam)).carrierDec) :    evalConsistency 𝓜(q, α) (b : ZMod q) stmt.avec stmt.bvec stmt.y      (extractedOpening 𝓜(q, α) (b : ZMod q) fam resp) := by  refine evalConsistency_of_star 𝓜(q, α) (b : ZMod q) stmt.avec stmt.bvec stmt.y    (extractedOpening 𝓜(q, α) (b : ZMod q) fam resp)    (gadgetMatrix 𝓜(q, α) (b : ZMod q) (2 ^ r) messageDigits *ᵥ (resp (central fam)).carrierDec)    ?_ ?_  · -- c3: verbatim c3 row of the central branch.    obtain ⟨-, -, hc3, -, -, -, -, -⟩ := hrel (central fam)    exact hc3  · -- c4 j: the coordinate-isolated, unit-divided c4-subtract chain.    intro j    obtain ⟨-, -, -, hc4s, -, -, -, -⟩ := hrel (sib fam j)    obtain ⟨-, -, -, hc4e, -, -, -, -⟩ := hrel (central fam)    rw [hw (sib fam j)] at hc4s    have hunit := slack_isUnit hq5 hκ fam hstar j    have hcoord : CoordEq j (fun i => (fam (sib fam j) i).val)        (fun i => (fam (central fam) i).val) :=      ShortChallenge.coordEq_val 𝓜(q, α) (coordEq_symm (sib_coordEq fam hstar j))    -- Subtract-and-isolate: the two branches' c4 rows, sharing `ŵ`, give `c̄ⱼ · wⱼ = aᵀ G Δzⱼ`.    have hchain : dot stmt.avec (gadgetMatrix 𝓜(q, α) (b : ZMod q) (2 ^ m) messageDigits *          ((Hachi.jMatrix 𝓜(q, α) (b : ZMod q) ((2 ^ m) * messageDigits) zDigits *              (resp (sib fam j)).zDec)           - (Hachi.jMatrix 𝓜(q, α) (b : ZMod q) ((2 ^ m) * messageDigits) zDigits *              (resp (central fam)).zDec)))        = ((fam (sib fam j) j).val - (fam (central fam) j).val) *            (gadgetMatrix 𝓜(q, α) (b : ZMod q) (2 ^ r) messageDigits *              (resp (central fam)).carrierDec) j := by      rw [matVecMul_sub, dot_sub,  hc4s,  hc4e,  Hachi.tensorG1_sub_challenge,        Hachi.tensorG1_coord_diff 𝓜(q, α) (b : ZMod q) messageDigits hcoord]    -- Divide by `c̄ⱼ`: the extracted message `sⱼ := c̄ⱼ⁻¹ •ᵥ Δzⱼ` recovers `wⱼ` under `aᵀ G`.    change (gadgetMatrix 𝓜(q, α) (b : ZMod q) (2 ^ r) messageDigits *          (resp (central fam)).carrierDec) j        = dot stmt.avec (gadgetMatrix 𝓜(q, α) (b : ZMod q) (2 ^ m) messageDigits *            (Ring.inverse ((fam (sib fam j) j).val - (fam (central fam) j).val) •ᵥ              ((Hachi.jMatrix 𝓜(q, α) (b : ZMod q) ((2 ^ m) * messageDigits) zDigits *                  (resp (sib fam j)).zDec)               - (Hachi.jMatrix 𝓜(q, α) (b : ZMod q) ((2 ^ m) * messageDigits) zDigits *                  (resp (central fam)).zDec))))    rw [matVecMul_scalarVecMul, dot_scalarVecMul, hchain,  mul_assoc,      Ring.inverse_mul_cancel _ hunit, one_mul]
Project
ArkLib
License
Apache-2.0
Commit
fad5cbf80877
Source
ArkLib/Commitments/Functional/Hachi/QuadEval/Soundness.lean:331-380

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