On permutability in semigroup varieties
نویسندگان
چکیده
منابع مشابه
On Universality of Semigroup Varieties
To Professor Jǐŕı Rosický on his 60th birthday Abstra t. A category K is called α-determined if every set of non-isomorphic Kobjects such that their endomorphism monoids are isomorphic has a cardinality less than α. A quasivariety Q is called Q-universal if the lattice of all subquasivarieties of any quasivariety of finite type is a homomorphic image of a sublattice of the lattice of all subqua...
متن کاملWeaker Universalities in Semigroup Varieties
A variety V has an alg-universal n-expansion if the addition of n nullary operations to algebras from V produces an alg-universal category. It is proved that any semigroup variety V containing a semigroup that is neither an inflation of a completely simple semigroup nor an inflation of a semilattice of groups has an alg-universal 3-expansion. We say that a variety V is var-relatively alg-univer...
متن کاملTwo Operators on the Lattice of Completely Regular Semigroup Varieties
In this paper, varieties of completely regular semigroups are studied. This paper is divided into six sections. Section 1 contains an introduction to varieties of completely regular semigroups and preliminaries. Most of the notation needed in this paper is given. In Section 2, the operators ←− ( ) and −→ ( ) on the lattice of subvarieties of varieties of completely regular semigroups are invest...
متن کاملLocal finiteness for Green’s relations in semigroup varieties
A semigroup S is called locally finite (respectively, periodic) if each finitely generated (respectively, each monogenic) subsemigroup in S is finite. A semigroup variety is locally finite (respectively, periodic) if so are all its members. Clearly, every locally finite variety is periodic but the converse is not true. The issues related to determining extra properties that distinguish locally ...
متن کاملSpecial Elements in the Lattice of Overcommutative Semigroup Varieties Revisited
We completely determine all distributive, codistributive, standard, costandard, and neutral elements in the lattice of overcommutative semigroup varieties, thus correcting a gap contained in [5].
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: Mathematica Bohemica
سال: 1991
ISSN: 0862-7959,2464-7136
DOI: 10.21136/mb.1991.126027