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The compact directed acyclic word graph (CDAWG) of a string $T$ of length $n$ takes space proportional just to the number $e$ of right extensions of the maximal repeats of $T$, and it is thus an appealing index for highly repetitive…

Data Structures and Algorithms · Computer Science 2017-09-27 Djamal Belazzougui , Fabio Cunial

In this paper, we propose and investigate algorithms for the structured orthogonal dictionary learning problem. First, we investigate the case when the dictionary is a Householder matrix. We give sample complexity results and show…

Signal Processing · Electrical Eng. & Systems 2025-03-25 Anirudh Dash , Aditya Siripuram

We examine the algebraic and geometric properties of a uni-directional GRU and word embeddings trained end-to-end on a text classification task. A hyperparameter search over word embedding dimension, GRU hidden dimension, and a linear…

Computation and Language · Computer Science 2018-03-09 Sean A. Cantrell

The problem of Text Indexing is a fundamental algorithmic problem in which one wishes to preprocess a text in order to quickly locate pattern queries within the text. In the ever evolving world of dynamic and on-line data, there is also a…

Data Structures and Algorithms · Computer Science 2012-08-21 Tsvi Kopelowitz

A simple linear-time algorithm for constructing a linear context-free tree grammar of size O(rg + r g log (n/r g))for a given input tree T of size n is presented, where g is the size of a minimal linear context-free tree grammar for T, and…

Data Structures and Algorithms · Computer Science 2018-10-09 Artur Jeż , Markus Lohrey

In this paper, we present the following results: (1) We propose a new \emph{dynamic compressed index} of $O(w)$ space, that supports searching for a pattern $P$ in the current text in $O(|P| f(M,w) + \log w \log |P| \log^* M (\log N + \log…

Data Structures and Algorithms · Computer Science 2016-04-07 Takaaki Nishimoto , I Tomohiro , Shunsuke Inenaga , Hideo Bannai , Masayuki Takeda

Offering rich contexts to Large Language Models (LLMs) has shown to boost the performance in various tasks, but the resulting longer prompt would increase the computational cost and might exceed the input limit of LLMs. Recently, some…

Computation and Language · Computer Science 2025-09-30 Wenhao Mao , Chengbin Hou , Tianyu Zhang , Xinyu Lin , Ke Tang , Hairong Lv

We study the problem of supporting queries on a string $S$ of length $n$ within a space bounded by the size $\gamma$ of a string attractor for $S$. Recent works showed that random access on $S$ can be supported in optimal…

Data Structures and Algorithms · Computer Science 2018-12-24 Nicola Prezza

Task-Oriented Parsing (TOP) enables conversational assistants to interpret user commands expressed in natural language, transforming them into structured outputs that combine elements of both natural language and intent/slot tags. Recently,…

Computation and Language · Computer Science 2023-12-19 Wenting Zhao , Ye Liu , Yao Wan , Yibo Wang , Qingyang Wu , Zhongfen Deng , Jiangshu Du , Shuaiqi Liu , Yunlong Xu , Philip S. Yu

We present novel variants of fully online LCA (FOLCA), a fully online grammar compression that builds a straight line program (SLP) and directly encodes it into a succinct representation in an online manner. FOLCA enables a direct encoding…

Data Structures and Algorithms · Computer Science 2014-01-30 Shirou Maruyama , Yasuo Tabei

The problem of finding factors of a text string which are identical or similar to a given pattern string is a central problem in computer science. A generalised version of this problem consists in implementing an index over the text to…

Data Structures and Algorithms · Computer Science 2016-02-04 Carl Barton , Tomasz Kociumaka , Solon P. Pissis , Jakub Radoszewski

A Lyndon word is a primitive string which is lexicographically smallest among cyclic permutations of its characters. Lyndon words are used for constructing bases in free Lie algebras, constructing de Bruijn sequences, finding the…

Data Structures and Algorithms · Computer Science 2013-01-03 Shoshana Marcus , Dina Sokol

In this article, we give a precise mathematical meaning to `linear? time' that matches experimental behaviour of the algorithm. The sorting algorithm is not our own, it is a variant of radix sort with counting sort as a subroutine. The true…

Computational Complexity · Computer Science 2019-01-01 Laurent Lyaudet

In this paper, we present a new data structure called the packed compact trie (packed c-trie) which stores a set $S$ of $k$ strings of total length $n$ in $n \log\sigma + O(k \log n)$ bits of space and supports fast pattern matching queries…

Data Structures and Algorithms · Computer Science 2017-10-11 Takuya Takagi , Shunsuke Inenaga , Kunihiko Sadakane , Hiroki Arimura

Suffix arrays encode the lexicographical order of all suffixes of a text and are often combined with the Longest Common Prefix array (LCP) to simulate navigational queries on the suffix tree in reduced space. In space-critical applications…

Data Structures and Algorithms · Computer Science 2017-11-02 Nicola Prezza

For a text given in advance, the substring minimal suffix queries ask to determine the lexicographically minimal non-empty suffix of a substring specified by the location of its occurrence in the text. We develop a data structure answering…

Data Structures and Algorithms · Computer Science 2016-02-01 Tomasz Kociumaka

A Random Access query to a string $T\in [0..\sigma)^n$ asks for the character $T[i]$ at a given position $i\in [0..n)$. In $O(n\log\sigma)$ bits of space, this fundamental task admits constant-time queries. While this is optimal in the…

Data Structures and Algorithms · Computer Science 2026-05-13 Anouk Duyster , Tomasz Kociumaka

Dependency trees have proven to be a very successful model to represent the syntactic structure of sentences of human languages. In these structures, vertices are words and edges connect syntactically-dependent words. The tendency of these…

Computation and Language · Computer Science 2024-03-05 Lluís Alemany-Puig , Ramon Ferrer-i-Cancho

We use reinforcement learning to learn tree-structured neural networks for computing representations of natural language sentences. In contrast with prior work on tree-structured models in which the trees are either provided as input or…

Computation and Language · Computer Science 2016-11-29 Dani Yogatama , Phil Blunsom , Chris Dyer , Edward Grefenstette , Wang Ling

Large Language Models (LLMs), such as GPT, are considered to learn the latent distributions within large-scale web-crawl datasets and accomplish natural language processing (NLP) tasks by predicting the next token. However, this mechanism…

Computation and Language · Computer Science 2025-02-04 Kun-Peng Ning , Jia-Yu Yao , Yu-Yang Liu , Mu-Nan Ning , Li Yuan