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Project-declaredLean 4.31.0 · mathlib@fabf563a7c95

Gs existence

GuruswamiSudan.gs_existence

Plain-language statement

GS existence with rate-corrected degree bound (ρ = k/n). Requires k > 1 for the counting argument and m ≥ 1 for multiplicity.

Exact Lean statement

theorem gs_existence (k n : ℕ) (ωs : Fin n ↪ F) (f : Fin n → F)
    (hk : 1 < k) (hn : n ≠ 0) (hm : 1 ≤ m) :
    ∃ Q, Conditions k m (gs_degree_bound k n m) ωs f Q

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem gs_existence (k n : ) (ωs : Fin n ↪ F) (f : Fin n  F)    (hk : 1 < k) (hn : n  0) (hm : 1  m) :     Q, Conditions k m (gs_degree_bound k n m) ωs f Q := by  set D := gs_degree_bound k n m  have hcount := gs_numVars_gt_numConstraints_of_gt_one hn hk hm  obtain c, hc_ne, hc_zero := exists_nonzero_solution_gen k n m ωs f D hcount  use coeffsToPoly k D c  refine ?_, ?_, ?_, ?_  · -- ne_zero    have h_inj : Function.Injective (coeffsToPoly (F := F) k D) := by      have : Function.Injective (linearCombination F        (fun p : weigthBoundIndices k D  monomial (F := F) p.1.1 p.1.2)) :=        linearIndependent_monomials.comp _ (fun p q h  by aesop)      exact this.comp (LinearEquiv.injective _)    exact fun h  hc_ne <| h_inj <| by simpa using h  · -- weightedDegree    convert Option.some_le_some.mpr (natWeightedDegree_coeffsToPoly_le k D c) using 1    exact weightedDegree_eq_natWeightedDegree  · -- roots    intro i    exact eval_eq_zero_of_constraint_zero hm fun s t hst  by      simp only [constraintMap, LinearMap.coe_mk, AddHom.coe_mk] at hc_zero      have := congr_fun (congr_fun hc_zero i) (s, t), Finset.mem_filter.2        Finset.mem_product.mpr Finset.mem_range.mpr (by linarith),          Finset.mem_range.mpr (by linarith), by linarith⟩⟩      aesop  · -- multiplicity    intro i    apply rootMultiplicity_ge_of_shift_zero    · have h_inj : Function.Injective (coeffsToPoly (F := F) k D) := by        have : Function.Injective (linearCombination F          (fun p : weigthBoundIndices k D  monomial (F := F) p.1.1 p.1.2)) :=          linearIndependent_monomials.comp _ (fun p q h  by aesop)        exact this.comp (LinearEquiv.injective _)      exact fun h  hc_ne <| h_inj <| by simpa using h    · intro s t hst      have h := congr_fun (congr_fun hc_zero i) (s, t), by        exact Finset.mem_filter.mpr Finset.mem_product.mpr Finset.mem_range.mpr (by linarith),          Finset.mem_range.mpr (by linarith), by linarith⟩⟩      -- Mirror the approach in polySol_multiplicity:      -- unfold constraintMap in hc_zero, extract component      simp only [constraintMap, LinearMap.coe_mk, AddHom.coe_mk] at hc_zero      have := congr_fun (congr_fun hc_zero i) (s, t), by        exact Finset.mem_filter.mpr Finset.mem_product.mpr Finset.mem_range.mpr (by linarith),          Finset.mem_range.mpr (by linarith), by linarith⟩⟩      aesop
Project
ArkLib
License
Apache-2.0
Commit
fad5cbf80877
Source
ArkLib/Data/CodingTheory/GuruswamiSudan/GuruswamiSudan.lean:993-1038

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Project-declaredLean 4.31.0

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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.

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Person-level attribution pending.

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Project-declaredLean 4.31.0

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ArkLib.Lattices.Ajtai.gadgetDecompose_lawful

Plain-language statement

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Source project: ArkLib

Person-level attribution pending.

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