Herstein's Lie theory revisited

has characterized those rings with involution J, with 1, and such that every symmetric element has an inverse under the additional hypothesis that S~~, the subring generated by ,S (the set of symmetric elements), is A, the ring itself.In this paper we raise the question as to when S~ = A under a weaker hypothesis and prove the following theorem.(A henceforth is such that 2A =A and 2x=0 implies x=0 for any xEA.)Theorem 1.Let A be a ring with 1 and suppose that S is a simple Jordan ring under the Jordan multiplication, s o t = st+ts for all s and t in S. Then either S~ = A or SEZ, the center of A, or K, the set o/ skew elements, is an ideal o/ A with K2EZ, K3 = (8), and S is an associative ring under Jordan multiplication.We note that Osborn proves that under his hypothesis, either A is a division ring; the direct sum of two division rings which are antiisomorphic, and / interchanges the summands; or 51 is a field under Jordan multiplication, K is an ideal of A where K2 = (d).A corollary to our result is Corollary 1.Let A be as in Theorem 1. Suppose /urther that A contains no nilpotent ideals.Then either A is simple or A is a direct sum o/ two simple rings which are anti-isomorphic and such that J interchanges the direct summands.

Let R be a 2-torsion free commutative ring with involution, and δ a nonzero derivation of R. Let S be the set of symmetric elements in R, and let K be the set of anti-symmetric elements in R. In this article, we investigate the semiprimeness of the Lie rings Sδ when δ is symmetric and Kδ when δ is anti-symmetric.

We study Lie ideals in two classes of triangular operator algebras: nest algebras and triangular UHF algebras. Our main results show that if 2 is a closed Lie ideal of the triangular operator algebra A, then there exist a closed associative ideal IC and a closed subalgebra Or of the diagonal A ni A* so that K C 2 C IC + Oc. INTRODUCTION Let A be an associative complex algebra. Under the Lie multiplication [x, y] xy yx, A becomes a Lie algebra. A Lie ideal in A is a linear manifold Z in A for which [a, k] c ? for every a E A and k c 2. In many instances, there is a close connection between the Lie ideal structure and the associative ideal structure of A. This connection has been investigated for prime rings in [6], in [3] for B($5) the set of bounded operators on a Hilbert space Si, and in [10] for certain von Neumann algebras. (See also [9, 4, 11].) In this paper we pursue this line of investigation for two classes of triangular operator algebras, namely nest algebras anld triangular UHF algebras. The authors would like to thank Frank A. Zorzitto for many helpful conversations. 1. WEAKLY CLOSED LIE IDEALS IN NEST ALGEBRAS Recall that a nest JK on a Hilbert space Si is a chain of closed subspaces of Si which is closed under the operations of arbitrary intersections and closed linear spans, and which includes {O} and S5. The nest algebra T(KJ) is the algebra of all operators on Se leaving every member of JK invariant. This is always closed in the weak operator topology. The diagonal D(KJ) of a nest algebra T(JK) is the von Neumann subalgebra 7(K) n T(K)*. If E, F E KV with E < F, then F E is called an interval of the nest. The nonzero minimal intervals are called atoms. A nest is atomic if the atoms of the nest span 55. We refer the reader to [1] for more information on nest algebras. Our main result, Theorem 12, shows that for every weakly closed Lie ideal Z in 7(JK), there exist a corresponding weakly closed associative ideal IC and a von Neumann subalgebra SK of O(A/) such that

Let A be a simple ring which is not a 4-dimensional algebra over a field of characteristic 2, and let U be a Lie ideal of A. Then Herstein proves in [2] that either U is contained in the center Z of A, or U contains [A, A ]; if in addition U is also assumed to be an associative ring and containls [A, A], then U=-A. Herstein and Baxter also prove in [1; 3], and [4] that [A, A] mod [A, A ]CnZ is a simple Lie ring. Our object here is to give a simple proof of this fact, basing our argument only on the results of [2] quoted above, though many of Herstein's ideas will be incorporated here without explicit mention. We first recall a few definitions and make some preliminary remarks. If u and a are elements of the ring A, [u, a] will designate uac-au, and [U, A ] will denote the module generated by all [u, a] where u is in U and a in A. U is an ideal of A if U is a module and if [U, A] is contained in U. If U and V are submodules of A then U+ V is the module generated by U and V. If U is a submodule of A we shall define U:A to be the set of elements x of A such that [x, A ] C U, thus [U: A, A ] is contained in U. It is easy to check that U:A is a ring from the identity [?v, a] = [u, va] + [v, au]. When U is a Lie ideal of A then U:A is also such. The following identities will be needed in the sequel; they are easy to verify:

Let [Formula: see text] be an [Formula: see text]-torsion free semiprime ring with center [Formula: see text] and [Formula: see text] be two [Formula: see text]-additive mappings with traces [Formula: see text], respectively. Sǒgǔtchǔ and Gǒlbasi [E. K. Sǒgǔtchǔ and Ǒ. Gǒlbasi, Commutativity theorems on Lie ideals with symmetric bi-derivations in semiprime rings, Asian Eur. J. Math. 16(7) (2023) 2350129] studied the following identities for symmetric bi-derivations: (i) [Formula: see text], (ii) [Formula: see text], (iii) [Formula: see text], (iv) [Formula: see text], (v) [Formula: see text], (vi) [Formula: see text], (vii) [Formula: see text], (viii) [Formula: see text], (ix) [Formula: see text], (x) [Formula: see text], (xi) [Formula: see text], (xii) [Formula: see text], for all [Formula: see text], where [Formula: see text] is a square closed Lie ideal of [Formula: see text] and then obtained that [Formula: see text] contains a nonzero central ideal. In this paper, we prove that the conclusion of above results holds for trace of any [Formula: see text]-additive mapping (not necessarily to be symmetric bi-derivation).

Let RG denote the group ring of a group G over a commutative ring with unity R. Given a homomorphism σ:G → {± 1} and an involution ϕ of the group G, an oriented invoultion σϕ of RG is defined in a natural way. We characterize when the set of symmetric elements under this involution is a subring. This gives a unified setting for earlier work of several authors.

Ordered ∗ -Rings

In 1996, the first author defined analogs of the concepts of complete (divisible), reduced, and periodic abelian groups, well-known in the theory of abelian groups, for arbitrary varieties of algebras. In 2021, the first author proposed a modification of the concepts of completeness and reducibility, which is more natural in the case of associative rings. The paper studies the modification of these concepts for associative rings. Artinian \(\mathbf{M}\)-complete, \(\mathbf{M}\)-reduced rings, and minimally \(\mathbf{M}\)-complete associative nilpotent rings, simple rings with unity, and finite rings are characterized.

A Galois theory of commutative rings

New results in the theory of associative and Lie rings

summary:Let $C$ be an associative commutative ring with 1. If $a\in C$, then $aC$ denotes the principal ideal generated by $a$. Let $l, m, n$ be nonzero elements of $C$ such that $mn \in lC$. The set of matrices $\left( \begin{smallmatrix} a_{11} & a_{12} a_{21} & -a_{11} \end{smallmatrix} \right) $, where $a_{11}\in lC$, $a_{12}\in mC$, $a_{21}\in nC$, forms a Lie ring under Lie multiplication and matrix addition. The paper studies properties of these Lie rings.

Let R be an associative ring , U be a nonzero Lie ideal of R. In this paper , we will present the definition of (U,R) – strongly derivation pair (d,g) , then we will get d=0 (resp. g=0 ) under certain conditions on d and g for (U,R) – strongly derivation pair (d,g) on semiprime ring . After that we will study prime rings , semiprime rings ,and rings that have a commutator left nonzero divisor with (U,R) – strongly derivation pair (d,g) , to obtain the notation of (U,R) – derivation .

Let $R$ be an associative ring with centre $Z$. The aim of this paper is to study how the ideal structure of the Lie ring of derivations of $R$, denoted $D(R)$, is determined by the ideal structure of $R$. If $R$ is a simple (respectively semisimple) finite-dimensional $Z$-algebra and δ$(z)$ = 0 for all δ ∈ $D(R)$, then every derivation of $R$ is inner and $D(R)$ is known to be a simple (respectively semisimple) Lie algebra (see [7, 5]). Here we are interested in extending these results to the case where $R$ is a prime or semi-prime ring.

Let R be a 2-torsion free ring and L a Lie ideal of R. An additive mapping F : R! R is called a generalized derivation on R if there exists a derivation d : R! R such that F (xy) = F (x)y+xd(y) holds for all x;y2 R. In the present paper we describe the action of generalized derivations satisfying several conditions on Lie ideals of semiprime rings.

Let R be a prime ring of characteristic different from 2, Z(R) its center, L a Lie ideal of R, and m, n, s, t ≥ 1 fixed integers with t ≤ m + n + s. Suppose that α is a non-trivial automorphism of R and let Φ(x, y) = [x, y]t – [x, y]m [α([x, y]),[x, y]]n [x, y]s. Thus, (a) if Φ(u, v) = 0 for any u, v ∈ L, then L ⊆ Z(R); (b) if Φ(u, v) ∈ Z(R) for any u, v ∈ L, then either L ⊆ Z(R) or R satisfies s4, the standard identity of degree 4. We also extend the results to semiprime rings.