On indexing and compressing finite automata

N Cotumaccio, N Prezza - Proceedings of the 2021 ACM-SIAM Symposium on …, 2021 - SIAM
An index for a finite automaton is a powerful data structure that supports locating paths
labeled with a query pattern, thus solving pattern matching on the underlying regular …

[HTML][HTML] Graphs cannot be indexed in polynomial time for sub-quadratic time string matching, unless SETH fails

M Equi, V Mäkinen, AI Tomescu - Theoretical Computer Science, 2023 - Elsevier
The string matching problem on a node-labeled graph G=(V, E) asks whether a given
pattern string P equals the concatenation of node labels of some path in G. This is a basic …

Graphs can be succinctly indexed for pattern matching in time

N Cotumaccio - 2022 Data Compression Conference (DCC), 2022 - ieeexplore.ieee.org
For the first time we provide a succinct pattern matching index for arbitrary graphs that can
be built in polynomial time, while improving both space and query time bounds from SODA …

Wheeler languages

J Alanko, G D'Agostino, A Policriti, N Prezza - Information and Computation, 2021 - Elsevier
The recently introduced class of Wheeler graphs, inspired by the Burrows-Wheeler
Transform (BWT) of a given string, admits an efficient index data structure for searching for …

On the complexity of BWT-runs minimization via alphabet reordering

J Bentley, D Gibney, SV Thankachan - arxiv preprint arxiv:1911.03035, 2019 - arxiv.org
The Burrows-Wheeler Transform (BWT) has been an essential tool in text compression and
indexing. First introduced in 1994, it went on to provide the backbone for the first encoding of …

Linear time construction of indexable founder block graphs

V Mäkinen, B Cazaux, M Equi, T Norri… - arxiv preprint arxiv …, 2020 - arxiv.org
We introduce a compact pangenome representation based on an optimal segmentation
concept that aims to reconstruct founder sequences from a multiple sequence alignment …

On the hardness and inapproximability of recognizing wheeler graphs

D Gibney, SV Thankachan - arxiv preprint arxiv:1902.01960, 2019 - arxiv.org
In recent years several compressed indexes based on variants of the Burrows-Wheeler
transformation have been introduced. Some of these index structures far more complex than …

Co-lexicographically ordering automata and regular languages-Part I

N Cotumaccio, G D'Agostino, A Policriti, N Prezza - Journal of the ACM, 2023 - dl.acm.org
The states of a finite-state automaton 𝒩 can be identified with collections of words in the
prefix closure of the regular language accepted by 𝒩. But words can be ordered, and among …

Computing matching statistics on Wheeler DFAs

A Conte, N Cotumaccio, T Gagie… - 2023 Data …, 2023 - ieeexplore.ieee.org
Matching statistics were introduced to solve the approximate string matching problem, which
is a recurrent subroutine in bioinformatics applications. In 2010, Ohlebusch et al.[SPIRE …

On the complexity of string matching for graphs

M Equi, V Mäkinen, AI Tomescu, R Grossi - ACM Transactions on …, 2023 - dl.acm.org
Exact string matching in labeled graphs is the problem of searching paths of a graph G=(V,
E) such that the concatenation of their node labels is equal to a given pattern string P [1. m] …