MSO-Enumeration Over SLP-Compressed Unranked Forests

Fuente: arXiv
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Autori principali: Lohrey, Markus, Schmid, Markus L.
Natura: Preprint
Pubblicazione: 2024
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author Lohrey, Markus
Schmid, Markus L.
author_facet Lohrey, Markus
Schmid, Markus L.
contents We study the problem of enumerating the answers to a query formulated in monadic second order logic (MSO) over an unranked forest F that is compressed by a straight-line program (SLP) D. Our main result states that this can be done after O(|D|) preprocessing and with output-linear delay (in data complexity). This is a substantial improvement over the previously known algorithms for MSO-evaluation over trees, since the compressed size |D| might be much smaller than (or even logarithmic in) the actual data size |F|, and there are linear time SLP-compressors that yield very good compressions on practical inputs. In particular, this also constitutes a meta-theorem in the field of algorithmics on SLP-compressed inputs: all enumeration problems on trees or strings that can be formulated in MSO-logic can be solved with linear preprocessing and output-linear delay, even if the inputs are compressed by SLPs. We also show that our approach can support vertex relabelling updates in time that is logarithmic in the uncompressed data. Our result extends previous work on the enumeration of MSO-queries over uncompressed trees and on the enumeration of document spanners over compressed text documents.
format Preprint
id arxiv_https___arxiv_org_abs_2403_03067
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle MSO-Enumeration Over SLP-Compressed Unranked Forests
Lohrey, Markus
Schmid, Markus L.
Formal Languages and Automata Theory
Databases
We study the problem of enumerating the answers to a query formulated in monadic second order logic (MSO) over an unranked forest F that is compressed by a straight-line program (SLP) D. Our main result states that this can be done after O(|D|) preprocessing and with output-linear delay (in data complexity). This is a substantial improvement over the previously known algorithms for MSO-evaluation over trees, since the compressed size |D| might be much smaller than (or even logarithmic in) the actual data size |F|, and there are linear time SLP-compressors that yield very good compressions on practical inputs. In particular, this also constitutes a meta-theorem in the field of algorithmics on SLP-compressed inputs: all enumeration problems on trees or strings that can be formulated in MSO-logic can be solved with linear preprocessing and output-linear delay, even if the inputs are compressed by SLPs. We also show that our approach can support vertex relabelling updates in time that is logarithmic in the uncompressed data. Our result extends previous work on the enumeration of MSO-queries over uncompressed trees and on the enumeration of document spanners over compressed text documents.
title MSO-Enumeration Over SLP-Compressed Unranked Forests
topic Formal Languages and Automata Theory
Databases
url https://arxiv.org/abs/2403.03067