Brown-McCoy Radical Research Articles

Brown-McCoy Radical in Restricted Graded Version

Some conjectures related to the radical theory of rings are still open. Hence, the research on the radical theory of rings is still being investigated by some prominent authors. On the other hand, some results on the radical theory of rings can be implemented in another branch or structure. In radical theory, it is interesting to bring some radical classes into graded versions. In this chance, we implement a qualitative method to conduct the research to bring the Brown-McCoy radical class to the restricted graded Brown-McCoy radical class as research objective. We start from some known facts on the Brown-McCoy radical class and furthermore, let G be a group, we explain the Brown-McCoy radical restricted with respect to the group G. The result of this paper, we describe the Brown-McCoy radical in restricted graded version and it is denoted by G^G. Furthermore, we also give the fact by explaining G^G (A)=(〖G(A))〗_G, for any ring A, as the final outcome of this paper.

On skew polynomial rings over locally nilpotent rings

We will show that skew polynomial rings in several variables over locally nilpotent rings cannot contain nonzero idempotent elements. We will also prove that such rings are Brown–McCoy radical.

Amitsur's property for skew polynomials of derivation type

We investigate when radicals $\mathfrak {F}$ satisfy Amit\-sur's property on skew polynomials of derivation type, namely, $\mathfrak {F}(R[x;\delta ])=(\mathfrak {F}(R[x;\delta ])\cap R)[x;\delta ].$ In particular, we give a new argument that the Brown-McCoy radical has this property. We also give a new characterization of the prime radical of $R[x;\delta ]$.

On polynomial rings over nil rings in several variables and the central closure of prime nil rings

We prove that the ring of polynomials in several commuting indeterminates over a nil ring cannot be homomorphically mapped onto a ring with identity, i.e. it is Brown-McCoy radical. It answers a question posed by Puczylowski and Smoktunowicz. We also show that the central closure of a prime nil ring cannot be a simple ring with identity, solving a problem due to Beidar.

Amitsur's property for skew polynomials of derivation type

We investigate when radicals $\mathfrak {F}$ satisfy Amit\-sur's property on skew polynomials of derivation type, namely, $\mathfrak {F}(R[x;\delta ])=(\mathfrak {F}(R[x;\delta ])\cap R)[x;\delta ].$ In particular, we give a new argument that the Brown-McCoy radical has this property. We also give a new characterization of the prime radical of $R[x;\delta ]$.

On graded Brown–McCoy radicals of graded rings

We investigate the graded Brown–McCoy and the classical Brown–McCoy radical of a graded ring, which is the direct sum of a family of its additive subgroups indexed by a nonempty set, under the assumption that the product of homogeneous elements is again homogeneous. There are two kinds of the graded Brown–McCoy radical, the graded Brown–McCoy and the large graded Brown–McCoy radical of a graded ring. Several characterizations of the graded Brown–McCoy radical are given, and it is proved that the large graded Brown–McCoy radical of a graded ring is the largest homogeneous ideal contained in the classical Brown–McCoy radical of that ring.

Chains of Prime Ideals and Primitivity of ℤ $\mathbb {Z}$ -Graded Algebras

In this paper we provide some results regarding affine, prime, \(\mathbb {Z}\)-graded algebras \(R=\bigoplus _{i\in \mathbb {Z}}R_{i}\) generated by elements with degrees 1,−1 and 0, with R0 finite-dimensional. The results are as follows. These algebras have a classical Krull dimension when they have quadratic growth. If Rk≠0 for almost all k then R is semiprimitive. If in addition R has GK dimension less than 3 then R is either primitive or PI. The tensor product of an arbitrary Brown-McCoy radical algebra of Gelfand Kirillov dimension less than three and any other algebra is Brown-McCoy radical.

On Radicals of Semirings and Related Problems

We develop an “external” Kurosh–Amitsur radical theory of semirings and obtain some fundamental results regarding the Jacobson and Brown–McCoy radicals of hemirings. Among others, we single out the following central results: characterizations and descriptions of semisimple hemirings; semiring versions of the classical Nakayama's and Hopkins's Lemmas and Jacobson–Chevalley Density Theorem; the fundamental relationship between the radicals of hemirings R and matrix hemirings M n (R); the matric-extensibleness (see, e.g., [4, Section 4.9]) of the radical classes of hemirings; the Morita invariance of the Jacobson– and Brown–McCoy-semisimplicity of semirings.

On radical classes of hemirings

Based on the concept of accessible subhemirings and inspired by the work on the general Kurosh-Amitsur radical theory for rings, this paper studies the lower radical classes and the hereditary radical classes of hemirings. We characterize radical classes of hemirings, and construct a lower radical class from a homomorphically closed class. We provide a necessary and sufficient condition under which an upper radical class of hemirings becomes hereditary and prove that an upper radical class of a regular class of semirings is hereditary. Besides, we show that the Brown-McCoy radical class and a Jacobson-type radical class are hereditary.

On prime ideals and radicals of polynomial rings and graded rings

We extend some known results on radicals and prime ideals from polynomial rings and Laurent polynomial rings to Z-graded rings, i.e, rings graded by the additive group of integers. The main of them concerns the Brown–McCoy radical G and the radical S, which for a given ring A is defined as the intersection of prime ideals I of A such that A/I is a ring with a large center. The studies are related to some open problems on the radicals G and S of polynomial rings and situated in the context of Koethe’s problem.

Primitivity in near-rings of continuous functions

In previous work, we studied primeness in near-rings and sandwich near-rings of continuous functions. In this paper we find conditions in certain cases for such near-rings to be 2- and 3-primitive. We also characterise the Jacobson-type radicals J2 and J3 and the Brown–McCoy radical of such near-rings in certain cases.

ON SUPERNILPOTENT RADICALS WITH THE AMITSUR PROPERTY

AbstractA radical α has the Amitsur property if α(A[x])=(α(A[x])∩A)[x] for all rings A. For rings R⊆S with the same unity, we call S a finite centralizing extension of R if there exist b1,b2,…,bt∈S such that S=b1R+b2R+⋯+btR and bir=rbi for all r∈R and i=1,2,…,t. A radical α is FCE-friendly if α(S)∩R⊆α(R) for any finite centralizing extension S of a ring R. We show that if α is a supernilpotent radical whose semisimple class contains the ring ℤ of all integers and α is FCE-friendly, then α has the Amitsur property. In this way the Amitsur property of many well-known radicals such as the prime radical, the Jacobson radical, the Brown–McCoy radical, the antisimple radical and the Behrens radical can be established. Moreover, applying this condition, we will show that the upper radical 𝒰(*k) generated by the essential cover *k of the class * of all *-rings has the Amitsur property and 𝒰(*k)(A[x])=𝒰(*k)(A)[x], where a semiprime ring R is called a *-ring if the factor ring R/I is prime radical for every nonzero ideal I of R. The importance of *-rings stems from the fact that a *-ring A is Jacobson semisimple if and only if A is a primitive ring.

RADICALS WITH THE α-AMITSUR PROPERTY

A radical γ of rings is said to have the Amitsur property if for all rings A, γ(A[X]) = (γ(A[X]) ∩ A)[X]. Let Xα denote a set of indeterminates of cardinality α. We say that γ has the α-Amitsur property if for all rings A, γ(A[Xα]) = (γ(A[Xα]) ∩ A)[Xα]. We study properties of this type of radicals and show relationships with other known radicals for rings. A ring A is said to be an absolute γ-ring if A[x1,…, xn] ∈ γ, for any n ∈ ℕ. We show that A is an absolute 𝔾-ring for the Brown–McCoy radical 𝔾, if and only if A is in the radical class S determined by the unitary strongly prime rings. Moreover, A is an absolute nil ring if and only if A is an absolute J-ring, where J denotes the Jacobson radical.

On the Behrens radical of matrix rings and polynomial rings

It is shown that the Behrens radical of a polynomial ring, in either commuting or non-commuting indeterminates, has the form of “polynomials over an ideal”. Moreover, in the case of non-commuting indeterminates, for a given coefficient ring, the ideal does not depend on the cardinality of the set of indeterminates. However, in contrast to the Brown–McCoy radical, it can happen that the polynomial ring R [ X ] in an infinite set X of commuting indeterminates over a ring R is Behrens radical while the polynomial ring R 〈 X 〉 in an infinite set Y of non-commuting indeterminates over R is not Behrens radical. This is connected with the fact that the matrix rings over Behrens radical rings need not be Behrens radical. The class of Behrens radical rings, which is closed under taking matrix rings, is described.

Maximal Ideals in Rings

This paper gives necessary and sufficient conditions which guarantee that a ring have maximal left, right, or two-sided ideals. The relations of rings without maximal ideals to the Jacobson and Brown-McCoy radical are discussed. Examples of rings without maximal ideals are given to illustrate the theory. Connections of existence of maximal ideals and the Axiom of Choice in Zermelo-Fraenkel set theory are noted.

On Polynomial and Multiplicative Radicals

We show that polynomial and multiplicative radicals in [1] are special cases of radicals defined by means of elements. We scrutinize the way of defining a radical γG by a subset G of polynomials in noncommuting indeterminates. Defining polynomial radicals, Drazin and Roberts [1] required that the set G be closed under composition of polynomials, and for multiplicative radicals two further conditions were demanded. We impose milder (in fact, necessary and sufficient) conditions, and call the so obtained radicals as weak polynomial and weak multiplicative radicals. The Baer (prime) radical is an example for a weak multiplicative (and so weak polynomial) radical which is not a polynomial (and so not a multiplicative) radical. The radical class of all rings A for which the polynomial ring A[x] is a Brown-McCoy radical ring (see [3]) is characterized in terms of commutators, and is shown to be a multiplicative radical.

Unitary strongly prime rings and related radicals

A unitary strongly prime ring is defined as a prime ring whose central closure is simple with identity element. The class of unitary strongly prime rings is a special class of rings and the corresponding radical is called the unitary strongly prime radical. In this paper we prove some results on unitary strongly prime rings. The results are applied to study the unitary strongly prime radical of a polynomial ring and also R-disjoint maximal ideals of polynomial rings over R in a finite number of indeterminates. From this we get relations between the Brown–McCoy radical and the unitary strongly prime radical of polynomial rings. In particular, the Brown–McCoy radical of R[X] is equal to the unitary strongly prime radical of R[X] and also equal to S(R)[X] , where S(R) denotes the unitary strongly prime radical of R, when X is an infinite set of either commuting or non-commuting indeterminates. For a PI ring R this holds for any set X.

MAXIMAL IDEALS IN THE ALGEBRA OF OPERATORS ON CERTAIN BANACH SPACES

AbstractFor a Banach space $\mathfrak{X}$, let $\mathcal{B}(\mathfrak{X})$ denote the Banach algebra of all continuous linear operators on $\mathfrak{X}$. First, we study the lattice of closed ideals in $\mathcal{B}(\mathfrak{J}_p)$, where $1 \lt p \t \infty$ and $\mathfrak{J}_p$ is the $p$th James space. Our main result is that the ideal of weakly compact operators is the unique maximal ideal in $\mathcal{B}(\mathfrak{J}_p)$. Applications of this result include the following.(i) The Brown–McCoy radical of $\mathcal{B}(\mathfrak{X})$, which by definition is the intersection of all maximal ideals in $\mathcal{B}(\mathfrak{X})$, cannot be turned into an operator ideal. This implies that there is no ‘Brown–McCoy’ analogue of Pietsch’s construction of the operator ideal of inessential operators from the Jacobson radical of $\mathcal{B}(\mathfrak{X})/\mathcal{A}(\mathfrak{X})$.(ii) For each natural number $n$ and each $n$-tuple $(m_1,\dots,m_n)$ in $\{k^2\mid k\in\mathbb{N}\}\cup\{\infty\}$, there is a Banach space $\mathfrak{X}$ such that $\mathcal{B}(\mathfrak{X})$ has exactly $n$ maximal ideals, and these maximal ideals have codimensions $m_1,\dots,m_n$ in $\mathcal{B}(\mathfrak{X})$, respectively; the Banach space $\mathfrak{X}$ is a finite direct sum of James spaces and $\ell_p$-spaces.Second, building on the work of Gowers and Maurey, we obtain further examples of Banach spaces $\mathfrak{X}$ such that all the maximal ideals in $\mathcal{B}(\mathfrak{X})$ can be classified. We show that the ideal of strictly singular operators is the unique maximal ideal in $\mathcal{B}(\mathfrak{X})$ for each hereditarily indecomposable Banach space $\mathfrak{X}$, and we prove that there are $2^{2^{\aleph_0}}$ distinct maximal ideals in $\mathcal{B}(\mathfrak{G})$, where $\mathfrak{G}$ is the Banach space constructed by Gowers to solve Banach’s hyperplane problem.AMS 2000 Mathematics subject classification: Primary 47D30; 47D50; 46H10; 16D30

On subhereditary radicals and reduced rings

We answer some open problems on subhereditary radicals of associative rings. In particular, we show that the Brown–McCoy radical is not subhereditary and that every left or right subhereditary and left or right stable radical satisfies all these properties. The latter of these results concerns, in fact, the question whether some classes of reduced rings are closed under one-sided essential extensions. We characterize several such classes.

BROWN-McCOY RADICALS FOR GENERAL NEAR-RINGS

Two possible ways of extending the Brown-McCoy radical to non-0-symmetric near-rings are discussed. If a Kurosh-Amitsur semisimple class So in the class No of 0-symmetric near-rings satisfies a certain condition on local units, then So is a Kurosh-Amitsur semisimple class also in the class N of all near-rings. So the subdirect closure of the class of simple 0-symmetric near-rings with identity is a Kurosh-Amitsur semisimple class in N with non-hereditary radical class. The Hoehnke radical eE determined by the class of simple near-rings with identity is not idempotent, though for every N ε N the radical eE (N) is the unique largest G-regular ideal of N. In both cases the radical classes are hereditary with respect to invariant ideals.