منابع مشابه
Semilattice of Bisimple Regular Semigroups
The main purpose of this paper is to show that a regular semigroup S is a semilattice of bisimple semigroups if and only if it is a band of bisimple semigroups and that this holds if and only if 3) is a congruence on S. It is also shown that a quasiregular semigroup 5 which is a rectangular band of bisimple semigroups is itself bisimple. In [3, Theorem 4.4] it was shown that a semigroup S is a ...
متن کاملΩ-terms over Finite Aperiodic Semigroups
This paper provides a characterization of pseudowords over the pseudovariety of all finite aperiodic semigroups that are given by ω-terms, that is that can be obtained from the free generators using only multiplication and the ω-power. A necessary and sufficient condition for this property to hold turns out to be given by the conjunction of two rather simple finiteness conditions: the nonexiste...
متن کاملThe Equational Theory of Ω-terms for Finite R-trivial Semigroups∗
A new topological representation for free profinite R-trivial semigroups in terms of spaces of vertex-labeled complete binary trees is obtained. Such a tree may be naturally folded into a finite automaton if and only if the element it represents is an ω-term. The variety of ω-semigroups generated by all finite R-trivial semigroups, with the usual interpretation of the ω-power, is then studied. ...
متن کاملOn bases of identities for the ω-variety generated by locally testable semigroups∗
In this paper, we exhibit an infinite basis of ω-identities for the ω-variety generated by the pseudovariety LSl, of semigroups which are locally semilattices, and we show that this ω-variety is not finitely based.
متن کاملω-Semigroups and the Fine Classification of Borel Subsets of Finite Ranks of the Cantor Space
The algebraic study of formal languages draws the equivalence between ω-regular languages and subsets of finite ω-semigroups. The ω-regular languages being the ones characterised by second order monadic formulas. Within this framework, in [1]we provide a characterisation of the algebraic counterpart of the Wagner hierarchy: a celebrated hierarchy of ω-regular languages. For this, we adopt a hie...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Proceedings of the Glasgow Mathematical Association
سال: 1966
ISSN: 2040-6185,2051-2104
DOI: 10.1017/s2040618500035346