Order-convexity in order topologies

In this survey the role of order-convexity in topologies compatible with a preference (i.e a negatively transitive partial order) is considered. Two main issues are highlighted:the (topoiogical) subspaces of preference ordered topological spaces, and the orderability of a topological space     

On a class of Sobolev scalar products in the polynomials

This paper discusses Sobolev orthogonal polynomials for a class of scalar products that contains the sequentially dominated products introduced by Lagomasino and Pijeira. We prove asymptotics for Markov type functions associated to the Sobolev scalar product and an extension of Widom's Theorem on the location of the zeroes of the orthogonal polynomials. In the case of measures supported in the real line, we obtain results related to the determinacy of the Sobolev moment problem and the completeness of the polynomials in a suitably defined weighted Sobolev space.     

Some Connections between Topological and Modal Logic

We study modal logics based on neighbourhood semantics using methods and theorems having their origin in topological model theory. We thus obtain general results concerning completeness of modal logics based on neighbourhood semantics as well as the relationship between neighbourhood and Kripke semantics. We also give a new proof for a known interpolation result of modal logic using an interpolation theorem of topological model theory.     

一类不确定线性切换系统二次鲁棒稳定性的充分条件

本文研究了一类不确定线性切换系统的二次鲁棒稳定性问题.首先利用矩阵集的严格完备性设计切换律,导出了二次鲁棒稳定的充分条件.同时得到了在任意切换策略下,当矩阵集的所有矩阵为负定时保证切换系统二次鲁棒稳定性.在适当的假设下,这些条件可以表示为矩阵不等式.最后,用数值例子对所得结果加以阐明,说明了文中结果的正确性.     

Completeness theorem for topological class models

A topological class logic is an infinitary logic formed by combining a first-order logic with the quantifier symbols O and C. The meaning of a formula closed by quantifier O is that the set defined by the formula is open. Similarly, a formula closed by quantifier C means that the set is closed. The corresponding models are a topological class spaces introduced by Ćirić and Mijajlović (Math Bakanica 1990). The completeness theorem is proved. This research was supported by the Ministry of Science, Technology and Development, Republic of Serbia, through Mathematical Institute, under grant 144013.     

双参数变形双模玻色算符的代数结构及其应用

构造了两个满足量子Heisenberg-Weyl代数的双参数变形双模玻色算符,研究了它们的代数结构,作为应用,分别构造了这两个算符二次幂及高次幂的本征态,证明了它们的完备性.     

Problems for Ordinary Differential Equations with Transmission Conditions

We investigate a boundary-functional problem with transmission conditions for ordinary differential-operator equation in Sobolev spaces with a weight. We prove an isomorphism, coerciveness with respect to the spectral parameter, completeness and Abel basis of a system of root functions of the problem. Obtained results in the article are new even in case of Sobolev spaces without the weight.     

On the cardinality of nonfinitely based functionally complete algebras

This paper proves that for each finite k≥ 4 there exist infinitely many pairwise term-inequivalent algebras of finite type with universe {0, 1, 2,..., k-1} which are functionally complete and inherently nonfinitely based. Received September 2, 1999; accepted in final form February 16, 2000.     

On certain Riesz families in vector-valued de Branges-Rovnyak spaces

We obtain criteria for the Riesz basis property for families of reproducing kernels in vector-valued de Branges-Rovnyak spaces H(b). In particular, it is shown that in several situations the property implies a special form for the function b. We also study the completeness of a related family.