Minimal Length of Nontrivial Solutions of the Isometry Equation and MacWilliams Extension Property with Respect to Weighted Poset Metric

02/03/2022
βˆ™
by   Yang Xu, et al.
βˆ™
0
βˆ™

For Rβ‰œ Mat_m(𝔽), the ring of all the mΓ— m matrices over the finite field 𝔽 with |𝔽|=q, and the left R-module Aβ‰œ Mat_m,k(𝔽) with m+1β©½ k, by deriving the minimal length of solutions of the related isometry equation, Dyshko has proved in <cit.> that the minimal code length n for A^n not to satisfy the MacWilliams extension property with respect to Hamming weight is equal to ∏_i=1^m(q^i+1). In this paper, using the MΓΆbius functions, we derive the minimal length of nontrivial solutions of the isometry equation with respect to a finite lattice. For the finite vector space π‡β‰œβˆ_iβˆˆΞ©π”½^k_i, a poset 𝐏=(Ξ©,β‰Ό_𝐏) and a map Ο‰:Ξ©βŸΆβ„^+ give rise to the (𝐏,Ο‰)-weight on 𝐇, which has been proposed by Hyun, Kim and Park in <cit.>. For such a weight, we study the relations between the MacWilliams extension property and other properties including admitting MacWilliams identity, Fourier-reflexivity of involved partitions and Unique Decomposition Property defined for (𝐏,Ο‰). We give necessary and sufficient conditions for 𝐇 to satisfy the MacWilliams extension property with the additional assumption that either 𝐏 is hierarchical or Ο‰ is identically 1, i.e., (𝐏,Ο‰)-weight coincides with 𝐏-weight, which further allow us to partly answer a conjecture proposed by Machado and Firer in <cit.>.

READ FULL TEXT

Please sign up or login with your details

Forgot password? Click here to reset