Search results for "semi"

Passive Air Sampling

2016

Zvaigžņotā Debess: 2017, Pavasaris (235)

2017

Contents: “ZVAIGŽŅOTĀ DEBESS” FORTY YEARS AGO: E.Mūkins. Clouds of Venus: Structure and Composition (abridged) ; J.Miezis. 3rd All-union Young Astronomers Gathering (abridged) ; DEVELOPMENTS in SCIENCE: K.Schwartz. New Discoveries in the Milky Way ; DISCOVERIES: I.Eglītis. Small Planets Get Latvian Names ; I.Pundure. Earth-mass World Revealed around Proxima Centauri ; SPACE RESEARCH and EXPLORATION: J.Jaunbergs. Mysteries of Saturn’s Clouds ; A.Slavinskis. Contribution of Estonian Student Satellite Programme ESTCube to Largest Challenges for Humanity ; R.Misa. Impossible Engine that Is likely Possible ; I.Pundure. ESO VLT to Search for Planets in Alpha Centauri System ; EARTH and COSMOS: J.…

A Criterium for the Strict Positivity of the Density of the Law of a Poisson Process

2011

We translate in semigroup theory our result (Leandre, 1990) giving a necessary condition so that the law of a Markov process with jumps could have a strictly positive density. This result express, that we have to jump in a finite number of jumps in a "submersive" way from the starting point to the end point if the density of the jump process is strictly positive in . We use the Malliavin Calculus of Bismut type of (Leandre, (2008;2010)) translated in semi-group theory as a tool, and the interpretation in semi-group theory of some classical results of the stochastic analysis for Poisson process as, for instance, the formula giving the law of a compound Poisson process.

Fixed point theorems for fuzzy mappings and applications to ordinary fuzzy differential equations

2014

Abstract Ran and Reurings (Proc. Am. Math. Soc. 132(5):1435-1443, 2004) proved an analog of the Banach contraction principle in metric spaces endowed with a partial order and discussed some applications to matrix equations. The main novelty in the paper of Ran and Reurings involved combining the ideas in the contraction principle with those in the monotone iterative technique. Motivated by this, we present some common fixed point results for a pair of fuzzy mappings satisfying an almost generalized contractive condition in partially ordered complete metric spaces. Also we give some examples and an application to illustrate our results. MSC:46S40, 47H10, 34A70, 54E50.

A synchronization property of pure subsemigroups of a free semigroup

1981

The History of Algebra in Mathematics Education

2006

In this chapter, we analyse key issues in algebra history from which some lessons can be extracted for the future of the teaching and learning of algebra. A comparative analysis of two types of pre-Vietan languages (before 16th century), and of the corresponding methods to solve problems, leads to conjecture the presence of didactic obstacles of an epistemological origin in the transition from arithmetic to algebraic thinking. This illustrates the value of historic and critical analysis for basic research design in mathematics education. Analysing the interrelationship between different evolution stages of the sign system of symbolic algebra and vernacular language supports the inference th…

A spectral mapping theorem for perturbed strongly continuous semigroups

1991

Continuous *-homomorphisms of Banach Partial *-algebras

2007

We continue the study of Banach partial *-algebras, in particular the question of the interplay between *-homomorphisms and biweights. Two special types of objects are introduced, namely, relatively bounded biweights and Banach partial *-algebras satisfying a certain Condition (S), which behave in a more regular way. We also present a systematic construction of Banach partial *-algebras of this type and exhibit several examples.

Basic Measure Theory

2020

In this chapter, we lay the measure theoretic foundations of probability theory. We introduce the classes of sets (semirings, rings, algebras, σ-algebras) that allow for a systematic treatment of events and random observations. Using the measure extension theorem, we construct measures, in particular probability measures on σ-algebras. Finally, we define random variables as measurable maps and study the σ-algebras generated by certain maps.

Elliptic convolution operators on non-quasianalytic classes

2001

For those nonquasianalytic classes in which an extension of the classical Borel's theorem holds we show that every elliptic convolution operator is the composition of a translation and an invertible ultradifferential operator. This answers a question asked by Chou in: La transformation de Fourier complexe et l'equation de convolution, LNM 325, Berlin-Heidelberg-New York (1973).