论文标题
在放松的本地可解码代码上,用于锤击和插入误差
On Relaxed Locally Decodable Codes for Hamming and Insertion-Deletion Errors
论文作者
论文摘要
可局部解释的代码(LDC)是错误校正的代码$ C:σ^n \ rightarrowσ^m $带有超快速解码算法。它们在理论计算机科学的许多领域都是重要的数学对象,但是到目前为止,最好的结构具有$ n $中超级多项式的CodeWord Length $ m $,用于具有持续查询复杂性和恒定字母大小的代码。在一个非常令人惊讶的结果中,Ben-Sasson等人。展示了如何在二进制字母上构建具有恒定查询复杂性和几乎线性代码字的长度的放松版本的LDC(RLDC),并用它们来获得可显着改良的概率可检查证明的构造。在这项工作中,我们在标准的锤式错误设置中研究RLDC,并在插入和删除(INSDEL)错误设置中介绍它们的变体。 Ostrovsky和Paskin-Cherniavsky首先研究了Insdel LDC,并进一步激发了DNA随机访问生物技术的最新进展,其中目的是从DNA存储数据库中检索单个文件。我们的第一个结果是在二进制字母上进行2个查询的锤rldc的长度上的指数下限。这回答了古尔和拉奇什明确提出的一个问题。我们的结果表现出用于恒定量压缩RLDC的代码字长度上的“相变”行为。我们进一步在Insdel-Error设置中定义了RLDC的两个变体,一个弱和强的版本。一方面,我们构建了弱的INSDEL RLDC,其参数与锤式变体的参数相匹配。另一方面,我们证明了强大的INSDEL RLDC的指数下限。这些结果表明,尽管这些变体在锤子设置中是等效的,但在INSDEL设置中它们的差异很大。我们的结果也证明了锤rdcs和insdel rldcs之间的严格分离。
Locally Decodable Codes (LDCs) are error-correcting codes $C:Σ^n\rightarrow Σ^m$ with super-fast decoding algorithms. They are important mathematical objects in many areas of theoretical computer science, yet the best constructions so far have codeword length $m$ that is super-polynomial in $n$, for codes with constant query complexity and constant alphabet size. In a very surprising result, Ben-Sasson et al. showed how to construct a relaxed version of LDCs (RLDCs) with constant query complexity and almost linear codeword length over the binary alphabet, and used them to obtain significantly-improved constructions of Probabilistically Checkable Proofs. In this work, we study RLDCs in the standard Hamming-error setting, and introduce their variants in the insertion and deletion (Insdel) error setting. Insdel LDCs were first studied by Ostrovsky and Paskin-Cherniavsky, and are further motivated by recent advances in DNA random access bio-technologies, in which the goal is to retrieve individual files from a DNA storage database. Our first result is an exponential lower bound on the length of Hamming RLDCs making 2 queries, over the binary alphabet. This answers a question explicitly raised by Gur and Lachish. Our result exhibits a "phase-transition"-type behavior on the codeword length for constant-query Hamming RLDCs. We further define two variants of RLDCs in the Insdel-error setting, a weak and a strong version. On the one hand, we construct weak Insdel RLDCs with with parameters matching those of the Hamming variants. On the other hand, we prove exponential lower bounds for strong Insdel RLDCs. These results demonstrate that, while these variants are equivalent in the Hamming setting, they are significantly different in the insdel setting. Our results also prove a strict separation between Hamming RLDCs and Insdel RLDCs.