共查询到20条相似文献,搜索用时 31 毫秒
1.
Yu Qun CHEN Yun FAN Zhi Feng HAO 《数学学报(英文版)》2005,21(4):893-898
We characterize the lattice of all ideals of a Morita ring (semigroup) when the corresponding pair of rings (semigroups) in the Morita context are Morita equivalent s-unital (like-unitv) rings (semigroups). 相似文献
2.
The join A ∨ B of two semigroup varieties A and B is investigated. The latrine of subvarieties of A ∨ B is completely described, It is shown that this lattice is finite and non-modular and that all varieties in it are finitely based and finitely generated. 相似文献
3.
As a generalization of an orthodox semigroup in the class of regular semigroups, a type W semigroup was first investigated
by El-Qallali and Fountain. As an analogy of the type W semigroups in the class of abundant semigroups, we introduce the U-orthodox semigroups. It is shown that the maximum congruence μ contained in
on U-orthodox semigroups can be determined. As a consequence, we show that a U-orthodox semigroup S can be expressed by the spined product of a Hall semigroup W
U
and a V-ample semigroup (T,V). This theorem not only generalizes a known result of Hall-Yamada for orthodox semigroups but also generalizes another known
result of El-Qallali and Fountain for type W semigroups.
This work was supported by National Natural Science Foundation of China (Grant No. 10671151) and Natural Science Foundation
of Shaanxi Province (Grant No. SJ08A06), and partially by UGC (HK) (Grant No. 2160123) 相似文献
4.
Using a construction theorem of cryptogroups and congruence methods, we determine an 18-element lattice, generated by {NOBG, ROBG, OBG, NBA, RBA, BA}, of subvarieties of completely regular semigroups.
This work was supported by the National Natural Science Foundation of China (Grant No. 10871161) and the Research Foundations
for Doctor Programme of Southwest University (Grant Nos. SWNUB2005020, SWNUB2008001) 相似文献
5.
We investigate certain semigroup varieties formed by nilpotent extensions of
orthodox normal bands of commutative periodic groups. Such semigroups are shown
to be both structurally periodic and structurally commutative, and are therefore
structurally inverse semigroups. Such semigroups are also shown to be dense
semilattices of structurally group semigroups. Making use of these structure
decompositions, we prove that the subvariety lattice of any variety comprised of
such semigroups is isomorphic to the direct product of the following three
sublattices: its sublattice of all structurally trivial semigroup varieties, its
sublattice of all semilattice varieties, and its sublattice of all group
varieties. We conclude, therefore, that to completely describe this lattice, we
must first describe completely the lattice of all structurally trivial semigroup
varieties, since the other two are well known lattices. 相似文献
6.
We study various notions of weak injectivity of acts over a Clifford semigroup. In addition we characterize weak self-injectivities
of several classes of Clifford semigroups constructed via particular kinds of groups and group homomorphisms.
Research of X. Zhang supported by the China Scholarship Council No. 2006101056.
Research of Y. Wang supported by National Natural Science Foundation of China Research Grant 10571181. 相似文献
7.
Xiangfei Ni 《Semigroup Forum》2009,78(1):34-53
The concept of quasi-adequate transversals is introduced. Some properties and characterizations for abundant semigroups with
a multiplicative quasi-adequate transversal are obtained. In particular, a structure theorem for such abundant semigroups
is given. Finally, some special cases are considered.
This research was partially supported by the National Natural Science Foundation of China (No. 10571077) and the Natural Science
Foundation of Gansu Province (No. 3ZS052-A25-017). 相似文献
8.
This paper determines all commutative zero divisor semigroups whose zero divisor graph is a complete graph (finite or infinite),
or a complete graph (finite or infinite) with one additional end vertex, and gives formulas for the numbers of all such semigroups
with n elements.
The research of T. Wu is supported by the National Natural Science Foundation of China (Grant No. 10671122) and the Natural
Science Foundation of Shanghai (Grant No. 06ZR14049). 相似文献
9.
Norman R. Reilly 《Semigroup Forum》2009,78(1):157-182
It is shown that, within the class of Rees-Sushkevich varieties that are generated by completely (0-) simple semigroups over
groups of exponent dividing n, there is a hierarchy of varieties determined by the lengths of the products of idempotents that will, if they fall into
a group ℋ-class, be idempotent. Moreover, the lattice of varieties generated by completely (0-) simple semigroups over groups
of exponent dividing n, with the property that all products of idempotents that fall into group ℋ-classes are idempotent, is shown to be isomorphic
to the direct product of the lattice of varieties of groups with exponent dividing n and the lattice of exact subvarieties of a variety generated by a certain five element completely 0-simple semigroup. 相似文献
10.
A filter in a semigroup is a subsemigroup whose complement is an ideal. (Alternatively, in a quasiordered semigroup, a slightly more general definition can be given.) We prove a number of results related to filters in a semigroup and the lattice of filters of a semigroup. For instance, we prove that every complete algebraic lattice can be the lattice of filters of a semigroup. We prove that every finite semigroup is a homomorphic image of a finite semigroup whose lattice of filters is boolean and which belongs to the pseudovariety generated by the original semigroup. We describe filter lattices of some well-known semigroups such as full transformation semigroups of finite sets (which are three-element chains) and free semigroups (which are boolean). 相似文献
11.
B. V. Novikov 《Journal of Mathematical Sciences》1994,72(4):3223-3225
The structure of additive semigroups generated by finite sets of n -dimensional vectors with positive integral coordinates is investigated. It is proved that each such semigroup contains a sub-semigroup isomorphic to a convex hull (in the lattice) of this semigroup.Translated from Ukrainskii Geometricheskii Sbornik, No. 35, pp. 99–103, 1992. 相似文献
12.
The lattice of idempotent distributive semiring varieties 总被引:7,自引:0,他引:7
A solution is given for the word problem for free idempotent distributive semirings. Using this solution the latticeL (ID) of subvarieties of the variety ID of idempotent distributive semirings is determined. It turns out thatL (ID) is isomorphic to the direct product of a four-element lattice and a lattice which is itself a subdirect product of four
copies of the latticeL(B) of all band varieties. ThereforeL(ID) is countably infinite and distributive. Every subvariety of ID is finitely based.
Project supported by the National Natural Science Foundation of China (Grant No. 19761004) and the Provincial Applied Fundamental
Research Foundation of Yunnan (96a001z). 相似文献
13.
14.
We classify all the Weierstrass semigroups of a pair of points on a curve of genus 3, by using its canonical model in the plane. Moreover, we count the dimension of the moduli of curves which have a pair of points with a specified Weierstrass semigroup.This work has been supported by the Japan Society for the Promotion of Science and the Korea Science and Engineering Foundation (Project No. 976-0100-001-2). Also the first author is partially supported by Korea Research Foundation Grant (KRF-99-005-D00003). 相似文献
15.
Contraction Integrated Semigroups and Their Application to Continuous-time Markov Chains 总被引:11,自引:0,他引:11
YangRongLI 《数学学报(英文版)》2003,19(3):605-618
We introduce the notion of the contraction integrated semigroups and give the Lumer-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their application, a necessary and sufficient condition for q-matrices Q generating a contraction integrated semigroup is given, and a necessary and sufficient condition for a transition function to be a Feller-Reuter-Riley transition function is also given in terms of its q-matrix. 相似文献
16.
17.
Tolerance relations on eventually regular semigroups 总被引:1,自引:0,他引:1
Hengwu Zheng 《Semigroup Forum》1996,53(1):135-139
A semigroup is called eventually regular if a power of each element is regular. Regular and group-bound semigroups are each
eventually regular. A tolerance relation on an eventually regular semigroup is introduced, and Lallement's result for regular
semigroups is generalized to eventually regular semigroups. Weakly compatible tolerances on semigroups are studied.
This research was partially supported by the National Science Foundation of Qufu Normal University. The author wishes to thank
T. E. Hall for his comments and help in preparing this paper for publication. 相似文献
18.
Yu Qiang Li 《数学学报(英文版)》2009,25(8):1379-1388
It is proved by the theory of semigroup that the Ornstein-Uhlenbeck type process with jumps can arise from the fluctuation limit of a sequence of Jirina processes with immigration under suitable moments conditions. 相似文献
19.
We show that many important varieties and sets of varieties of semigroups may be defined by relatively simple and transparent
first-order formulas in the lattice of all semigroup varieties. 相似文献
20.
Pseudovarieties of completely regular semigroups 总被引:1,自引:0,他引:1
Francis Pastijn 《Semigroup Forum》1991,42(1):1-46