论文标题
改进的高阶MDS代码的场尺寸范围
Improved Field Size Bounds for Higher Order MDS Codes
论文作者
论文摘要
高阶MDS代码是Brakensiek,Gopi和Makam最近引入的MDS代码的有趣概括(IEEETrans。Inf。Theolod。2022)。在以后的工作中,它们被证明与最佳列表可解码的代码和最大可回收张量代码密切相关。因此,(明确的)高阶MDS代码在小场上是一个重要的开放问题。高阶MDS代码用$ \ operatatorName {mds}(\ ell)$表示,其中$ \ ell $表示通用性的顺序,$ \ operatatorName {mds}(2)$代码等于通常的MDS代码。最好的先前下限在$(n,k)$ - $ \ operatorName {mds}(\ ell)$代码为$ω__\ ell(n^{\ ell-1})$的字段大小上,而最佳的(非解释)上限是$ o_ o_ o_ o_ o_ o _ el ell(n^n^n^k(el ell-el-el-el-el-1)$ extient in Dimention niste niste niste niste ate niste, 在这项工作中,我们几乎缩小了上限和下限之间的指数差距。我们表明,$(n,k)$ - $ \ operatotorName {mds}(3)$代码需要一个大小$ω_k(n^{k-1})$的字段,该字段接近已知的上限。使用高阶MDS代码和最佳列表可解码代码之间的连接,我们表明,即使对于2个列表大小,符合最佳列表描述的Singleton BONDON BONDEN的代码也需要指数式字段大小;这解决了Shangguan和Tamo(Stoc 2020 / siam J.计算2023)的一个公开问题。 我们还提供了$(n,k)$ - $ \ operatotorname {mds}(\ ell)$代码的明确构造,大小$ n^{(\ ell k)^{o(\ ell k)}} $。我们仍然没有最佳构造的最小非平地案例是$(n,3)$ - $ \ operatatorName {mds}(3)$。在这种情况下,现场尺寸的已知下限为$ω(n^2)$,对于非明确结构而言,最著名的上限为$ O(n^5)$,而$ O(N^{32})$用于显式结构。在本文中,我们对$ o(n^3)$的字段的明确构造非常接近最佳。
Higher order MDS codes are an interesting generalization of MDS codes recently introduced by Brakensiek, Gopi and Makam (IEEE Trans. Inf. Theory 2022). In later works, they were shown to be intimately connected to optimally list-decodable codes and maximally recoverable tensor codes. Therefore (explicit) constructions of higher order MDS codes over small fields is an important open problem. Higher order MDS codes are denoted by $\operatorname{MDS}(\ell)$ where $\ell$ denotes the order of generality, $\operatorname{MDS}(2)$ codes are equivalent to the usual MDS codes. The best prior lower bound on the field size of an $(n,k)$-$\operatorname{MDS}(\ell)$ codes is $Ω_\ell(n^{\ell-1})$, whereas the best known (non-explicit) upper bound is $O_\ell(n^{k(\ell-1)})$ which is exponential in the dimension. In this work, we nearly close this exponential gap between upper and lower bounds. We show that an $(n,k)$-$\operatorname{MDS}(3)$ codes requires a field of size $Ω_k(n^{k-1})$, which is close to the known upper bound. Using the connection between higher order MDS codes and optimally list-decodable codes, we show that even for a list size of 2, a code which meets the optimal list-decoding Singleton bound requires exponential field size; this resolves an open question from Shangguan and Tamo (STOC 2020 / SIAM J. on Computing 2023). We also give explicit constructions of $(n,k)$-$\operatorname{MDS}(\ell)$ code over fields of size $n^{(\ell k)^{O(\ell k)}}$. The smallest non-trivial case where we still do not have optimal constructions is $(n,3)$-$\operatorname{MDS}(3)$. In this case, the known lower bound on the field size is $Ω(n^2)$ and the best known upper bounds are $O(n^5)$ for a non-explicit construction and $O(n^{32})$ for an explicit construction. In this paper, we give an explicit construction over fields of size $O(n^3)$ which comes very close to being optimal.