New associative and nonassociative Gelfand-Naimark theorems.
Nice connecting paths in connected components of sets of algebraic elements in a Banach algebra
Generalizing earlier results about the set of idempotents in a Banach algebra, or of self-adjoint idempotents in a -algebra, we announce constructions of nice connecting paths in the connected components of the set of elements in a Banach algebra, or of self-adjoint elements in a -algebra, that satisfy a given polynomial equation, without multiple roots. In particular, we prove that in the Banach algebra case every such non-central element lies on a complex line, all of whose points satisfy the...
Nil, nilpotent and PI-algebras
The notions of nil, nilpotent or PI-rings (= rings satisfying a polynomial identity) play an important role in ring theory (see e.g. [8], [11], [20]). Banach algebras with these properties have been studied considerably less and the existing results are scattered in the literature. The only exception is the work of Krupnik [13], where the Gelfand theory of Banach PI-algebras is presented. However, even this work has not get so much attention as it deserves. The present paper...
Nilpotent elements and solvable actions.
In what follows we shall describe, in terms of some commutation properties, a method which gives nilpotent elements. Using this method we shall describe the irreducibility for Lie algebras which have Levi-Malçev decomposition property.
Nilpotente Liesche Gruppen haben symmetrische Gruppenalgebren.
Noetherian Banach Algebras are Finite Dimensional.
Nonassociative normed algebras: geometric aspects
Introduction. The aim of this paper is to review some relevant results concerning the geometry of nonassociative normed algebras, without assuming in the first instance that such algebras satisfy any familiar identity, like associativity, commutativity, or Jordan axiom. In the opinion of the author, the most impressive fact in this direction is that most of the celebrated natural geometric conditions that can be required for associative normed algebras, when imposed on a general nonassociative...
Nonassociative real H*-algebras.
We prove that, if A denotes a topologically simple real (non-associative) H*-algebra, then either A is a topologically simple complex H*-algebra regarded as real H*-algebra or there is a topologically simple complex H*-algebra B with *-involution τ such that A = {b ∈ B : τ(b) = b*}. Using this, we obtain our main result, namely: (algebraically) isomorphic topologically simple real H*-algebras are actually *-isometrically isomorphic.
Nonassociative ultraprime normed algebras.
Recently M. Mathieu [9] has proved that any associative ultraprime normed complex algebra is centrally closed. The aim of this note is to announce the general nonassociative extension of Mathieu's result obtained by the authors [2].
Noncommutative Jordan algebras containing minimal inner ideals
Noncommutative uniform algebras
We show that a real Banach algebra A such that ||a²|| = ||a||² for a ∈ A is a subalgebra of the algebra of continuous quaternion-valued functions on a compact set X.
Noninvertibility preservers on Banach algebras
It is proved that a linear surjection , which preserves noninvertibility between semisimple, unital, complex Banach algebras, is automatically injective.
Non-Replaceable Matrices.
Non-trivial derivations on commutative regular algebras.
Necessary and sufficient conditions are given for a (complete) commutative algebra that is regular in the sense of von Neumann to have a non-zero derivation. In particular, it is shown that there exist non-zero derivations on the algebra L(M) of all measurable operators affiliated with a commutative von Neumann algebra M, whose Boolean algebra of projections is not atomic. Such derivations are not continuous with respect to measure convergence. In the classical setting of the algebra S[0,1] of all...
Norm conditions for uniform algebra isomorphisms
In recent years much work has been done analyzing maps, not assumed to be linear, between uniform algebras that preserve the norm, spectrum, or subsets of the spectra of algebra elements, and it is shown that such maps must be linear and/or multiplicative. Letting A and B be uniform algebras on compact Hausdorff spaces X and Y, respectively, it is shown here that if λ ∈ ℂ / 0 and T: A → B is a surjective map, not assumed to be linear, satisfying then T is an ℝ-linear isometry and there exist an...
Normal Hilbert modules over the ball algebra A(B)
The normal cohomology functor is introduced from the category of all normal Hilbert modules over the ball algebra to the category of A(B)-modules. From the calculation of -groups, we show that every normal C(∂B)-extension of a normal Hilbert module (viewed as a Hilbert module over A(B) is normal projective and normal injective. It follows that there is a natural isomorphism between Hom of normal Shilov modules and that of their quotient modules, which is a new lifting theorem of normal Shilov...
Normal subgroups of classical groups over Banach algebras.
Normally subregular systems in normed algebras
Norm-decreasing isomorphism on hermitian elements and the group of isometric and invertible multipliers of a Banach algebra
Normed algebras with involution.