Reed Solomon multilinear Correlated Agreement Nat
reedSolomon_multilinearCorrelatedAgreement_Nat
Plain-language statement
Corollary 3.7: RS Codes have Tensor-Style Proximity Gaps (Unique Decoding) Example 4.1 shows that ε=n is tight for RS codes (Ben+23 Thm 4.1 is sharp).
Exact Lean statement
theorem reedSolomon_multilinearCorrelatedAgreement_Nat [Nontrivial (ReedSolomon.code α k)]
{e : ℕ} (hk : k ≤ Fintype.card ι)
(he : e ≤ (Code.uniqueDecodingRadius (C := (ReedSolomon.code α k : Set (ι → A))))) :
∀ (ϑ : ℕ), (hϑ_gt_0 : ϑ > 0) → δ_ε_multilinearCorrelatedAgreement_Nat (F := A) (A := A)
(ι := ι) (C := (ReedSolomon.code α k : Set (ι → A)))
(ϑ := ϑ) (e := e) (ε := Fintype.card ι)Formal artifact
Lean source
theorem reedSolomon_multilinearCorrelatedAgreement_Nat [Nontrivial (ReedSolomon.code α k)] {e : ℕ} (hk : k ≤ Fintype.card ι) (he : e ≤ (Code.uniqueDecodingRadius (C := (ReedSolomon.code α k : Set (ι → A))))) : ∀ (ϑ : ℕ), (hϑ_gt_0 : ϑ > 0) → δ_ε_multilinearCorrelatedAgreement_Nat (F := A) (A := A) (ι := ι) (C := (ReedSolomon.code α k : Set (ι → A))) (ϑ := ϑ) (e := e) (ε := Fintype.card ι) := by set n := Fintype.card ι intro ϑ hϑ_gt_0 u h_prob_tensor_gt set C_RS: ModuleCode ι A A := ReedSolomon.code α k have h_dist_RS := ReedSolomon.dist_eq_of_le (F := A) (α := α) (n := k) (ι := ι) (h := hk) have h_dist_CRS : ‖(C_RS : Set (ι → A))‖₀ = n - k + 1 := h_dist_RS -- 1. Apply ReedSolomon_ProximityGapAffineLines_UniqueDecoding (BCIKS20 Thm 4.1) have h_fincard_n : Fintype.card (ι) = n := by rfl have h_affine_gap_base : e_ε_correlatedAgreementAffineLinesNat (F := A) (A := A) (ι := ι) (C := C_RS) (e := e) (ε := n) := by let res := ReedSolomon_ProximityGapAffineLines_UniqueDecoding (A := A) (hk := by omega) (e := e) he rw [h_fincard_n] at res exact res -- 2. Check condition ε ≥ e + 1 for Theorem 3.1 have h_eps_ge_e1 : n ≥ e + 1 := by simp only [uniqueDecodingRadius] at he simp_rw [h_dist_CRS] at he simp only [add_tsub_cancel_right] at he rw [ge_iff_le]; apply Nat.le_of_lt_succ; have h_lt : e + 1 < (n - k) / 2 + 1 + 1 := by omega have h_le : (n - k) / 2 + 1 ≤ n := by exact Nat.sub_div_two_add_one_le n k hk omega -- 3. Apply Theorem 3.1 inductively (or just state it's needed for Thm 3.6) have h_affine_gap_interleaved : ∀ m, (hm: m ≥ 1) → letI : Nonempty (Fin m × (ι)) := by apply nonempty_prod.mpr constructor · exact Fin.pos_iff_nonempty.mp hm · omega e_ε_correlatedAgreementAffineLinesNat (F := A) (A := InterleavedSymbol A (Fin m)) (ι := ι) (C := C_RS ^⋈ (Fin m)) e (Fintype.card (ι)) := by intro m hm let res := affine_gaps_lifted_to_interleaved_codes (MC := C_RS) (F := A) (A := A) (hε := h_eps_ge_e1) (e := e) (m := m) (hProximityGapAffineLines := h_affine_gap_base) (he := he) rw [h_fincard_n] exact res -- 4. Apply Theorem 3.6 (AER24) let RS_tensor_gap := interleaved_affine_gaps_imply_tensor_gaps (MC := C_RS) (h_interleaved_gaps := by rw [h_fincard_n] at h_affine_gap_interleaved exact h_affine_gap_interleaved) h_affine_gap_base exact RS_tensor_gap ϑ hϑ_gt_0 u h_prob_tensor_gt- Project
- ArkLib
- License
- Apache-2.0
- Commit
- fad5cbf80877
- Source
- ArkLib/Data/CodingTheory/ProximityGap/DG25/ReedSolomon.lean:121-173
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Affine gaps lifted to interleaved codes
affine_gaps_lifted_to_interleaved_codes
Project documentation
This lemma proves the final algebraic step in the DG25 Theorem 3.1 proof. It shows that if R > e + 1, then e * (R / (R - 1)) < e + 1. The intuition is that the fraction R / (R - 1) is always greater than 1, but as R gets larger, it gets closer to 1. The hypothesis R > e + 1 provides a strong enough bound to ensure the product e * (fraction) do...
Source project: ArkLib
Person-level attribution pending.
Gadget Decompose coeff
ArkLib.Lattices.Ajtai.gadgetDecompose_coeff
Plain-language statement
The k-th coefficient (k < deg φ) of a gadget-decomposition block is exactly the corresponding digit of the corresponding input coefficient.
Source project: ArkLib
Person-level attribution pending.
Gadget Decompose lawful
ArkLib.Lattices.Ajtai.gadgetDecompose_lawful
Plain-language statement
The base-b gadget decomposition is a lawful gadget decomposition.
Source project: ArkLib
Person-level attribution pending.