The introduction of stochastic process algebra (SPA) has had a profound impact on the field of performance modelling. Hillston’s PEPA has been at the forefront of this development [1]. There are a number of reasons why the use of stochastic process algebra is attractive to the stochastic modeller. The parsimonious set of operators creates an almost programming-like simplicity to model specifica...

Abstract 2-Local derivations on real matrix algebras over unital semi-prime Banach are considered. Using the analogue of result that any 2-local derivation algebra $$M_{2^n}(A)$$ M 2 n ( A ...

Let be the Lie algebra of semi-direct sum real vector space and sets all matrices. In this paper, a Frobenius functional is constructed in order for to dimension 8. Moreover, bilinear form corresponding symplectic. Then obtained symplectic induces left-symmetric structures on . other words, algebra. particular, we give formulas its structure explicitely. The case higher type are still an open p...

Since the advent of Markovian Process Algebras, users have requested the ability to employ a greater variety of action distribution. We present a conservative extension to the popular Markovian process algebra, PEPA, which incorporates generally distributed sojourn-times for action duration. Just as a PEPA model generates a Markov chain for analysis purposes, so semi-Markov PEPA produces a semi...

Abstract In this paper, we prove a general result saying that under certain hypothesis an embedding of affine vertex algebra into $W$–algebra is conformal if and only their central charges coincide. This extends our previous obtained in the case minimal $W$-algebras [ 3]. We also find sufficient condition showing levels are collapsing. new enables us to some $k$ where $W_{k}(sl(N), x, f )$ coll...

Semi-structured data are the core of new information systems. Developing dedicated tools is an important issue. This paper describes the basis of an architecture for the manipulation of semi-structured data. A conceptual data model is presented, it is based on labelled trees and its purpose is to provide the user with a view of data. A logical model and an associated algebra are also proposed; ...

The dramatic increase of mostly semi-structured genomic data, their heterogeneity and high variety, and the increasing complexity of biological applications and methods mean that many and very important challenges in biology are now challenges in computing and here especially in databases. In contrast to the many query-driven approaches advocated in the literature, we propose a new integrating ...

We have previously introduced Generalized Semi-Markovian Process Algebra (GSMPA), a process algebra based on ST semantics which is capable of expressing durational actions, where durations are expressed by general probability distributions. In this paper we introduce the calculus of Interactive Generalized Semi-Markov Processes (IGSMP), a variant of GSMPA where synchronizable actions are restri...

Let g be a finite dimensional complex semi-simple Lie algebra with Weyl group W and simple reflections S. For I ⊆ S let g I be the corresponding semi-simple subalgebra of g. Denote by W I the Weyl group of g I and let w • and w I • be the longest elements of W and W I , respectively. In this paper we show that the answer to Kostant's problem, i.e. whether the universal enveloping algebra surjec...

The purpose of this note is to study the radical and such concepts as semi-simplicity and simplicity for Lie algebras in terms of characteristic ideals. The program follows the outlines of part of a fundamental paper of Fitting on finite groups, and the final result displaying an isomorphism of an algebra 8 with no solvable characteristic ideals into the Lie algebra of derivations of a uniquely...