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Volume 65, Issue 2


Complexities of Relational Structures

David Hartman
  • Computer Science Institute of Charles University Charles University Malostranské nám. 25 CZ–118 00 Praha 1 CZECH REPUBLIC
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/ Jan Hubička
  • Computer Science Institute of Charles University Charles University Malostranské nám. 25 CZ-118 00 Praha 1 CZECH REPUBLIC
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/ Jaroslav Nešetřil
  • Computer Science Institute of Charles University Charles University Malostranské nám. 25 CZ-118 00 Praha 1 CZECH REPUBLIC
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Published Online: 2015-05-22 | DOI: https://doi.org/10.1515/ms-2015-0019


The relational complexity, introduced by G. Cherlin, G. Martin, and D. Saracino, is a measure of ultrahomogeneity of a relational structure. It provides an information on minimal arity of additional invariant relations needed to turn given structure into an ultrahomogeneous one. The original motivation was group theory. This work focuses more on structures and provides an alternative approach. Our study is motivated by related concept of lift complexity studied by Hubička and Nešetřil.

Keywords: relational complexity; lifting complexity


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About the article

Received: 2013-05-30

Accepted: 2013-06-06

Published Online: 2015-05-22

Published in Print: 2015-04-01

Citation Information: Mathematica Slovaca, Volume 65, Issue 2, Pages 229–246, ISSN (Online) 1337-2211, ISSN (Print) 0139-9918, DOI: https://doi.org/10.1515/ms-2015-0019.

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