We give a necessary and sufficient condition for the preservation of finite products by a reflection of a variety of universal algebras into an idempotent subvariety. It is also shown that simple and semi-left-exact reflections into subvarieties of universal algebras are the same. It then follows that a reflection of a variety of universal algebras into an idempotent subvariety has stable units...

Let X be a Hilbert bimodule over a C-algebra A and OX = A ⋊X Z. Using a finite section method we construct a sequence of completely positive contractions factoring through matrix algebras over A which act on sξs ∗ η as Schur multipliers converging to the identity. This shows immediately that for a finitely generated X the algebra OX inherits any standard approximation property such as nuclearit...

This work investigates the dynamics of modulated waves in a coupled nonlinear LC transmission line. By means of a method based on the semi-discrete limit and in suitably scaled coordinates, we derive the two-dimensional NLS equation governing the propagation of slowly modulated waves in the network. The exact transverse solution is found and the analytical criteria of stability of this solution...

Let T be a right exact functor from an abelian category ℬ into another $${\mathscr A}$$ . Then there exists p the product A} \times {\mathscr B}$$ to comma ( $$\left( {T \downarrow A}} \right)$$ ). In this paper, we study property of extension closure some classes objects in ), exactness and detailed description orthogonal given class $${\rm{P}}\left( {{\cal X},{\cal Y}} Moreover, characterize ...

Robust semi-definite programming problems with rational dependence on uncertainties are known to have a wide range of applications, in particular in robust control. It is well-established how to systematically construct relaxations on the basis of the full block S-procedure. In general such relaxations are expected to be conservative, but for concrete problem instances they are often observed t...

We introduce left and right series of semi-braces. This allows to define nilpotent study the structure such semi-braces generalize some results, known for skew braces, B that set additive idempotents E is an ideal . Finally we concept a semi-brace show multiplicative group nilpotent.