Dist From Code le iff rel Dist From Code le
Code.distFromCode_le_iff_relDistFromCode_le
Plain-language statement
A word u is close to a code C within an absolute error bound e if and only if it is close within the equivalent relative error bound e / n.
Exact Lean statement
theorem distFromCode_le_iff_relDistFromCode_le {C : Set (ι → F)} [Nonempty ι] (u : ι → F) (e : ℕ) :
Δ₀(u, C) ≤ e ↔ δᵣ(u, C) ≤ (e : ℝ≥0) / (Fintype.card ι : ℝ≥0)Formal artifact
Lean source
theorem distFromCode_le_iff_relDistFromCode_le {C : Set (ι → F)} [Nonempty ι] (u : ι → F) (e : ℕ) : Δ₀(u, C) ≤ e ↔ δᵣ(u, C) ≤ (e : ℝ≥0) / (Fintype.card ι : ℝ≥0) := by have h_n_pos : 0 < Fintype.card ι := Fintype.card_pos have h_n_pos_nnreal : 0 < (Fintype.card ι : ℝ≥0) := by exact_mod_cast h_n_pos rw [closeToCode_iff_closeToCodeword_of_minDist] conv_rhs => rw [←ENNReal.coe_div (hr := by simp only [ne_eq, Nat.cast_eq_zero, Fintype.card_ne_zero, not_false_eq_true])] rw [relCloseToCode_iff_relCloseToCodeword_of_minDist (u := u) (C := C) (δ := (e : ℝ≥0) / (Fintype.card ι : ℝ≥0))] apply exists_congr intro v simp only [and_congr_right_iff] intro hv_mem rw [pairRelDist_le_iff_pairDist_le] simp only [isUnit_iff_ne_zero, ne_eq, Nat.cast_eq_zero, Fintype.card_ne_zero, not_false_eq_true, IsUnit.div_mul_cancel, Nat.floor_natCast]- Project
- ArkLib
- License
- Apache-2.0
- Commit
- fad5cbf80877
- Source
- ArkLib/Data/CodingTheory/Basic/RelativeDistance.lean:328-343
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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.