Geometrically closed positive varieties of languages
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F22%3A00129037" target="_blank" >RIV/00216224:14310/22:00129037 - isvavai.cz</a>
Result on the web
<a href="https://www.sciencedirect.com/science/article/pii/S0890540121000249#" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0890540121000249#</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.ic.2021.104709" target="_blank" >10.1016/j.ic.2021.104709</a>
Alternative languages
Result language
angličtina
Original language name
Geometrically closed positive varieties of languages
Original language description
A recently introduced operation of geometrical closure on formal languages is investigated from the viewpoint of algebraic language theory. Positive varieties V containing exclusively languages with regular geometrical closure are fully characterised by inclusion of V in W, a known positive variety arising in the study of the commutative closure. It is proved that the geometrical closure of a language from the intersection of W with the variety of all star-free languages SF always falls into RLT, which is introduced as a subvariety of R, the variety of languages recognised by R-trivial monoids. All classes between RLT and W∩SF are thus geometrically closed: for instance, the level 3/2 of the Straubing-Thérien hierarchy, the DA-recognisable languages, or the variety R. It is also shown that W∩SF is the largest geometrically closed positive variety of star-free languages, while there is no largest geometrically closed positive variety of regular languages.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10201 - Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)
Result continuities
Project
<a href="/en/project/GA19-12790S" target="_blank" >GA19-12790S: Effective characterizations of classes of finite semigroups and formal languages</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2022
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Information and Computation
ISSN
0890-5401
e-ISSN
1090-2651
Volume of the periodical
288
Issue of the periodical within the volume
October
Country of publishing house
US - UNITED STATES
Number of pages
17
Pages from-to
1-17
UT code for WoS article
000873951700008
EID of the result in the Scopus database
2-s2.0-85101014909