Definitions and notation: Let A be a central simple algebra of degree n over a field k of characteristic different from 2. An involution on A is a ring antiautomorphism of order at most 2. An involution σ is of the first kind if σ|k = Idk, and of the second kind if σ|k is a non trivial involution on k, denoted by .̄ In the last case, k is a quadratic extension of the subfield k0 fixed by .̄ So we...

We give the avoidance indices for all unary patterns with involution.

We show that most of the theory of Hermitian Banach algebras can be proved for normed ∗-algebras without the assumption of completeness. The condition r(x) ≤ p(x) for all x (where p(x) = r(x∗x)1/2 is the Pták function), which is essential in the theory of Hermitian Banach algebras, is replaced for normed ∗-algebras by the condition r(x + y) ≤ p(x) + p(y) for all x, y. In case of Banach ∗-algebr...

We give a necessary and su¢ cient condition for a bounded involution lattice to be isomorphic to the direct square of its invariant part. This result is applied to show relations between related lattices of an algebra: For instance, generalizing some earlier results of G. Czédli and L. Szabó it is proved that any algebra admits a connected compatible partial order whenever its quasiorder lattic...

Article history: Received 5 March 2013 Received in revised form 4 April 2014 Accepted 15 July 2014 Available online 23 July 2014 Communicated by J. Karhumäki

It is often inevitable to introduce an indefinite-metric space in quantum field theory, for example, which is explained for the sake of the manifestly covariant quantization of the electromagnetic field. We show two more evident mathematical reasons why such indefinite metric appears. The first idea is the replacement of involution on an algebra. For an algebra A with an involution † such that ...

Increased levels of pro-inflammatory markers and decreased levels of anti-inflammatory markers in the breast tissue can result in local inflammation. We aimed to investigate whether local inflammation in the breast tissue is associated with age-related lobular involution, a process inversely related to breast cancer risk. Levels of eleven pro- and anti-inflammatory markers were assessed by immu...

In this paper we study the conditions under which an involution becomes metabolic over a quadratic field extension. We characterise those involutions that become metabolic over a given separable quadratic extension. We further give an example of an anisotropic orthogonal involution that becomes isotropic over a separable quadratic extension.

This is a continuation to the study of EP elements, normal elements and partial isometries in rings with involution. The aim of this paper is to give the negative solution to three conjectures on this subject. Moreover, some new characterizations of EP elements in rings with involution are presented.