Algebra, Logic and Topology

 

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details

Author(s)
Ana Paula Escada; Jorge Almeida;

Title
The globals of pseudovarieties of ordered semigroups containing B2 and an application to a problem proposed by Pin

Abstract
Given a basis of pseudoidentities for a pseudovariety of ordered semigroups containing the 5-element aperiodic Brandt semigroup B_2, under the natural order, it is shown that the same basis, over the most general graph over which it can be read, defines the global. This is used to show that the global of the pseudovariety of level 3/2 of Straubing-Thérien's concatenation hierarchy has infinite vertex rank.

Journal
RAIRO Theoretical Informatics and Applications

Volume
39

Year
2005

Issue

Page(s)
1-29

 
     
 

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