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Asymptotic fraction of profile vectors captured by Varshamov AECC intersection

Prove that for any integers q, ℓ, and d, with S = {0,1,...,q−1}^ℓ and N = |S|, if (H, b) is a Varshamov-type (N, d+1) asymmetric error-correcting code over the finite field F_p that contains the all-ones vector, then the leading constant c(H, S) in the asymptotic expansion of |C(H, b) ∩ (n; S)| satisfies c(H, S) ≥ c(q, ℓ)/p^d, where c(q, ℓ) is the leading constant in the asymptotic expansion of |(n; S)| for S = {0,1,...,q−1}^ℓ.

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Background

The paper defines c(q, ℓ) as the leading coefficient in the asymptotic formula |(n; S)| = c(q, ℓ) n{|S|−|V(S)|} + O(n{|S|−|V(S)|−1}) for S = {0,1,...,q−1}ℓ, using Ehrhart theory for counting integer points in polytopes corresponding to profile vectors.

For a Varshamov-type (N, d+1) AECC C(H, b) over F_p that contains the all-ones vector and with N = |S|, the authors define c(H, S) as the leading coefficient in the asymptotic lower bound |C(H, b) ∩ (n; S)| ≥ c(H, S) n{|S|−|V(S)|} + O(n{|S|−|V(S)|−1}). The conjecture posits that asymptotically the intersection captures at least a 1/pd fraction of all profile vectors, matching the naive pigeonhole expectation.

References

We conclude this section with a conjecture on the relation between c(q,ℓ) and c(H,S). Conjecture Fix q,ℓ,d. Choose H and p such that (H,b) is an (N,d+1)-AECC containing 1. Let c(q,ℓ) and c(H,S) be the constants defined in Corollaries \ref{cor:cql} and \ref{cor:cHS}, respectively. Then c(H,S)\ge c(q,ℓ)/pd.

Codes for DNA Sequence Profiles (1502.00517 - Kiah et al., 2015) in Conjecture, end of Subsection 6.2 (Lower Bounds on Code Sizes)