7 citations · 16 across the 8 of their papers we have counts for
5 papers · 1 filter
Pseudovarieties of ordered completely regular semigroups
Jorge Almeida, Ondřej Klíma
This paper is a contribution to the theory of finite semigroups and their classification in pseudovarieties, which is motivated by its connections with computer science. The questi…
On the insertion of n-powers
J. Almeida, O. Klíma
In algebraic terms, the insertion of -powers in words may be modelled at the language level by considering the pseudovariety of ordered monoids defined by the inequality $1\le x…
Reducibility versus definability for pseudovarieties of semigroups
J. Almeida, O. Klíma
It is easy to show that a pseudovariety which is reducible with respect to an implicit signature for the equation can also be defined by -identities. We present severa…
The omega-inequality problem for concatenation hierarchies of star-free languages
J. Almeida, O. Klíma, M. Kunc
The problem considered in this paper is whether an inequality of omega-terms is valid in a given level of a concatenation hierarchy of star-free languages. The main result shows th…
Representations of relatively free profinite semigroups, irreducibility, and order primitivity
J. Almeida, O. Klíma
We establish that, under certain closure assumptions on a pseudovariety of semigroups, the corresponding relatively free profinite semigroups freely generated by a non-singleton fi…