分配P-代数的核理想与余核滤子

本文的主要结果是给出了分配P-代数中一个理想成为核理想的充要条件,同时提出了余核滤子的概念,研究了核理想与余核滤子之间的某些内在联系.     

Properties of algebras of primary order with one ternary Mal'tsev operation

We study properties of free solvable p-algebras and of p-algebras of primary orders. It is shown that a free solvable p-algebra is embeddable in a subdirect product of algebras with these orders. An example of a simple non-Abelian p-algebra of a primary order is constructed, and we also give an example of a solvable non-nilpotent p-algebra of any finite order not less than 6.Translated fromAlgebra i Logika, Vol. 34, No. 2, pp. 132-141, March-April, 1995.Partially supported by the Russian Foundation for Fundamental Research, the Program Universities of Russia, and the Russian Ministry of Science, Higher Schools of Learning, and Technical Policy, grant No. 2-11-1-2.     

伪补MS-代数的滤子同余关系

在伪补MS-代数上引入余核滤子和完全滤子的概念,研究伪补MS-代数的余核滤子和完全滤子的性质,获得了余核滤子和完全滤子生成的同余关系的表达式,证明了具有余核滤子的最小同余关系有同余一致性.     

Congruence Permutable Symmetric Extended de Morgan Algebras

An algebra A is said to be congruence permutable if any two congruences on it are permutable. This property has been investigated in several varieties of algebras, for example, de Morgan algebras, p-algebras, Kn,0-algebras. In this paper, we study the class of symmetric extended de Morgan algebras that are congruence permutable. In particular we consider the case where A is finite, and show that A is congruence permutable if and only if it is isomorphic to a direct product of finitely many simple algebras.     

PMS-代数中的正则理想

本文提出伪补 Ｍ Ｓ 代数（简称 Ｐ Ｍ Ｓ 代数）中正则理想、正则同余关系的概念,研究正则理想与核理想、０ 理想之间的关系,讨论正则同余关系的性质,得到若干结果     

On the Notion of a Semi-Abelian Category in the Sense of Palamodov

In the sense of Palamodov, a preabelian category is semi-abelian if for every morphism the natural morphism between the cokernel of its kernel and the kernel of its cokernel is simultaneously a monomorphism and an epimorphism. In this article we present several conditions which are all equivalent to semi-abelianity. First we consider left and right semi-abelian categories in the sense of Rump and establish characterizations of these notions via six equivalent properties. Then we use these properties to deduce the characterization of semi-abelianity. Finally, we investigate two examples arising in functional analysis which illustrate that the notions of right and left semi-abelian categories are distinct and in particular that such categories occur in nature.     

KERNEL IDEALS AND CONGRUENCES ON MS-ALGEBRAS

In this article, the authors describe the largest congruence induced by a kernel ideal of an MS-algebra and characterize those MS-algebras on which all the congruences are in a one-to-one correspondence with the kernel ideals.     

Theorem on semisimple lie p-algebras

The known fact on the decomposability of any semisimple Lie algebra over an algebraically closed field of characteristic zero into a direct sum of simple ideals remains true in the case of characteristic p > 0. It is also shown that a semisimple Lie p-algebra, admitting a faithful p-representation of dimension n < p–1 has such a decomposition. Its direct factors are Lie p-algebras of the classical type with a non-degenerate bilinear form of trace. The restriction n < p–1 is essential. Bibliography has 6 references.Translated from Matematicheskie Zametki, Vol. 2, No. 5, pp. 465–474, November, 1967.     

$$\lambda $$ λ -Semidirect products of inverse monoids are weakly Schreier extensions

Semigroup Forum - A split extension of monoids with kernel $$k :N \rightarrow G$$ , cokernel $$e :G \rightarrow H$$ and splitting $$s :H \rightarrow G$$ is weakly Schreier if each element $$g \in...     

Congruences and Ideals of Effect Algebras

This paper is devoted to a general investigation of congruences and ideals in effect algebras. One of our main results is the existence of an order isomorphism between Riesz congruences and Riesz ideals. We also answer an open question of Dvureenskij and Pulmannová by showing that an ideal is a Riesz ideal if and only if it is closed under generalized Sasaki projections.     

Automata all of whose congruences are inner

A congruence on an automaton A is called inner if it is the kernel of a certain endomorphism on A. We propose a characterization of automata, all of whose congruences are inner.     

The strong endomorphism kernel property for modular p-algebras and for distributive lattices

We study the strong endomorphism kernel property (SEKP) for some classes of universal algebras. Using the Katriňák-Mederly triple construction, we prove a universal equivalent condition under which a modular p-algebra has SEKP. As a consequence, we characterize distributive lattices with top element that enjoy SEKP. Using Priestley duality, we also characterize unbounded distributive lattices that have SEKP.     

A natural map in local cohomology

Let R be a Noetherian ring, \(\mathfrak{a}\) an ideal of R, M an R-module and n a non-negative integer. In this paper we first study the finiteness properties of the kernel and the cokernel of the natural map \(f\colon\operatorname{Ext}^{n}_{R}(R/\mathfrak{a},M)\to \operatorname{Hom}_{R}(R/\mathfrak{a},\mathrm{H}^{n}_{\mathfrak{a}}(M))\), under some conditions on the previous local cohomology modules. Then we get some corollaries about the associated primes and Artinianness of local cohomology modules. Finally we will study the asymptotic behavior of the kernel and the cokernel of the natural map in the graded case.     

Toeplitz plus Hankel Operators with Infinite Index

We study Toeplitz plus Hankel operators acting between Lebesgue spaces on the unit circle, and having symbols which contain standard almost periodic discontinuities. Conditions are obtained under which these operators are right-invertible and with infinite kernel dimension, left-invertible and with infinite cokernel dimension or simply not normally solvable.     

Invertibility theory for Toeplitz plus Hankel operators and singular integral operators with flip

It is well known that a Toeplitz operator is invertible if and only if its symbols admits a canonical Wiener-Hopf factorization, where the factors satisfy certain conditions. A similar result holds also for singular integral operators. More generally, the dimension of the kernel and cokernel of Toeplitz or singular integral operators which and Fredholm operators can be expressed in terms of the partial indices of an associated Wiener-Hopf factorization problem.In this paper we establish corresponding results for Toeplitz plus Hankel operators and singular integral operators with flip under the assumption that the generating functions are sufficiently smooth (e.g., Hölder continuous). We are led to a slightly different factorization problem, in which pairs , instead of the partial indices appear. These pairs provide the relevant information about the dimension of the kernel and cokernel and thus answer the invertibility problem.     

双重伪补Ockham代数的理想与滤子

描述了双重伪补Ockham代数的理想和滤子的某些性质。我们证明了一个双重伪补Ockham代数的核理想格与其余核滤子格同构。     

New concepts for completely regular semigroups

Let 𝒞? denotes the variety of completely regular semigroups considered with the unary operation of inversion. The global study of the lattice of subvarieties of 𝒞? depends heavily on various decompositions. Some of the most fruitful among these are induced by the kernel and the trace relations. In their turn, these relations are induced by the kernel and the trace relations on the lattice of congruences on regular semigroups. These latter admit the concepts of kernel and trace of a congruence. The kernel and the trace relations for congruences were transferred to kernel and trace relations on varieties but the kernel and trace got no analogue for varieties.

We supply here the kernel and the trace of a variety which induce the relations of their namesake. For the local and core relations, we also define the local and core of a variety. All the new concepts are certain subclasses of 𝒞?. In this way, we achieve considerable similarity of the new concepts with those for congruences. We also correct errors in two published papers.     

Congruences and ideals on Boolean modules: a heterogeneous point of view

Definitions for heterogeneous congruences and heterogeneous ideals on a Boolean module $\mathcal {M}$ are given and the respective lattices $\mathrm{Cong}\mathcal {M}$ and $\mathrm{Ide}\mathcal {M}$ are presented. A characterization of the simple bijective Boolean modules is achieved differing from that given by Brink in a homogeneous approach. We construct the smallest and the greatest modular congruence having the same Boolean part. The same is established for modular ideals. The notions of kernel of a modular congruence and the congruence induced by a modular ideal are introduced to describe an isomorphism between $\mathrm{Cong}\mathcal {M}$ and $\mathrm{Ide}\mathcal {M}$. This isomorphism leads us to conclude that the class of the Boolean module is ideal determined.     

Universal algebras

A survey of the development of the theory of universal algebras in the years 1976–1988. Such basic directions of development of this theory as classes of universal algebras (varieties, quasivarieties, etc.), Mal'tsev conditions, congruences, sheaves, homomorphisms, subalgebras, products of algebras, clones of operations, completeness, systems of equations in algeberas, and connections with computer mathematics show up in it. Considerable attention is given to concrete classes of algebras (p-algebras, BCK-algebras, unary algebras, etc.).Translated from Itogi Nauki i Tekhniki, Seriya Algebra, Topologiya, Geometriya, Vol. 27, pp. 45–124, 1989.     

Finite Interval Convolution Operators with Transmission Property

We study convolution operators in Bessel potential spaces and (fractional) Sobolev spaces over a finite interval. The main purpose of the investigation is to find conditions on the convolution kernel or on a Fourier symbol of these operators under which the solutions inherit higher regularity from the data. We provide conditions which ensure the transmission property for the finite interval convolution operators between Bessel potential spaces and Sobolev spaces. These conditions lead to smoothness preserving properties of operators defined in the above-mentioned spaces where the kernel, cokernel and, therefore, indices do not depend on the order of differentiability. In the case of invertibility of the finite interval convolution operator, a representation of its inverse is presented in terms of the canonical factorization of a related Fourier symbol matrix function.