Spectral theory for non-associative complete normed algebras and automatic continuity

This paper concerns normed algebras whose product is free of the requirement of associativity. For these algebras, a very natural notion of spectrum is provided and basic spectral properties of (associative) Banach algebras are extended to this general non-associative setting. These results are applied to generalize Rickart's dense-range homomorphism theorem. Our approach sheds some light on the classical associative theory.     

Polar Conic Set-Valued Map in Vector Optimization. Continuity and Derivability

In the context of vector optimization, several results are stated mainly about the continuity and the derivability of a conic set-valued map (the polar conic function) having a close relation with the positive efficient points, the ideal points and other distinguished elements of the efficient line. The contingent cone to the set of the general positive quasiefficient points at a point x ₀ is also related with the frontier of the dual cone of the image at x ₀ of the polar conic function. This work was partially supported by Grant SEJ2006–15401–C04–02 of Spanish Ministerio de Ciencia y Tecnología and Grant S-0505/tic/0230-D3 of Comunidad Autónoma de Madrid. The authors are grateful to the referees for suggestions which led to improving the paper.     

A cardinality-constrained robust model for the assignment problem in Home Care services

Home Care includes medical, paramedical and social services which are delivered to patients at their domicile rather than in hospital. Managing human and material resources in Home Care services is a difficult task, as the provider has to deal with peculiar constraints (e.g., the continuity of care, which imposes that a patient is always cared for by the same nurse) and to manage the high variability of patients’ demands. One of the main issues encountered in planning Home Care services under continuity of care requirement is the nurse-to-patient assignment. Despite the importance of this topic, the problem is only marginally addressed in the literature, where continuity of care is usually treated as a soft-constraint rather than as a hard one. Uncertainty is another relevant feature of nurse-to-patient assignment problem, and it is usually managed adopting stochastic programming or analytical policies. However, both these approaches proved to be limited, even if they improve the quality of the assignments upon those actually provided in practice. In this paper, we develop a cardinality-constrained robust assignment model, which allows exploiting the potentialities of a mathematical programming model without the necessity of generating scenarios. The developed model is tested on real-life instances related to a relevant Home Care provider operating in Italy, in order to evaluate its capability of reducing the costs related to nurses’ overtimes.     

第二积分中值函数

通过上、下确界定义,给出了"第二积分中值函数"的定义,并对"第二积分中值函数"的单调性、可积性、连续性、可导性等分析性质进行了系统的讨论.     

On the stability of time-varying differential equations *

This paper deals with stability of time-varying differential equations. New asymptotic stability conditions for time-varying continuous systems with more general assumptions are given. The Gronwall's inequality and its discrete-time versions play a crucial role in our investigation.     

Intuitionistic Fuzzy Slight Continuity

In this paper,we introduce the notion of intuitionistic fuzzy slightly continuity as a generalizing fuzzy continuity.Basic properties and preservation theorems of intuitionistic fuzzy slightly continuous functions are obtained.     

Roots and polynomials as Homeomorphic spaces

We provide a unified, elementary, topological approach to the classical results stating the continuity of the complex roots of a polynomial with respect to its coefficients, and the continuity of the coefficients with respect to the roots. In fact, endowing the space of monic polynomials of a fixed degree n and the space of n roots with suitable topologies, we are able to formulate the classical theorems in the form of a homeomorphism. Related topological facts are also considered.     

Boundedly complete weak-Cauchy basic sequences in Banach spaces with the PCP

It is proved that every non-trivial weak-Cauchy sequence in a Banach space with the PCP (the Point of Continuity Property) has a boundedly complete basic subsequence. The following result, due independently to S. Bellenot and C. Finet, is then deduced as a corollary. If a Banach space X has separable dual and the PCP, then every non-trivial weak-Cauchy sequence in X has a subsequence spanning an order-one quasi-reflexive space.