Žarko Popović

Semilattices of Archimedean semigroups

M. S. Putcha, in 1973, gave the first complete description of semilattices of Archimedean semigroups. Other characterizations of this class of semigroups have been given by T. Tamura in 1972, by S. Bogdanovic and M. Ciric in 1992 and by M. Ciric and S. Bogdanovic in 1993. In this paper, for m, n ∈ N, we define a relation ρ(m,n) and prove that it is a congruence relation on an arbitrary semigroup. Using the congruence relation ρ(m,n) we will give some new characterizations of semilattices of Archimedean semigroups. At the end we describe hereditary properties of semilattices of k-Archimedean semigroups.

EFFICIENCY ESTIMATION OF COMMERCIAL BANKS BASED ON FINANCIAL PERFORMANCE: INPUT ORIENTED DEA CRS/VRS MODELS

Abstract Measurement and evaluation of the bank’s operations efficiency requires analytical techniques that provide data beyond those available from the standard analysis of financial statements. The Data Envelopment Analysis (DEA) is a mathematical programming technique that offers valuable insights in finding inefficient banks taking into account the scope of the services and resources used to provide these banking services. The results of the DEA analysis can provide significant information to the bank’s management that can supplement the information obtained using traditional techniques for assessing efficiency. The assessment of banks’ efficiency in the Republic of Serbia is of particular importance due to intense competition and implemented banking reforms. Therefore, in this paper DEA analysis will be applied for the examination and assessment of the efficiency of the operations of Serbian banks during the period 2014-2016. The analysis will show which of the banks operates efficiently, where the efficiency of the banks is not at a satisfactory level, as well as the potential reasons for inefficiency.

Determination of Expert Group Preferences in the Multi-Criteria Model for the Analysis of Local Economic Environment

Abstract Local economic environment is characterised by a range of economic, social, political and demographic parameters, based on which we can perform its analysis. Heterogeneity of relevant characteristics of the local economic environment imposes multiple criteria analysis as one of the suitable tools for the evaluation. Assessment of local economic environment often falls within the scope of group decision-making, as it is usually performed on the basis of an analysis of preferences of economic subjects or relevant experts on the issue of the economic environment at the local level. Regardless of whether it is based on economic subjects or expert group, in order to form a multi-criteria model, it is necessary to generate preferences of individuals into a single weight coefficient, which shows groups’ preference on the importance of each criterion. The subject of this paper is determination of weight coefficients in the multi-criteria model for the analysis of local economic development based on the preferences from a group of experts, by applying adequate statistical tools, and then by ranking local governments according to the quality of business environment perceived by the expert group.In addition to descriptive statistics and testing the significance of differences, in the paper is applied multi-criteria method Simple Additive Weights - SAW.

GENERALIZED DIRECTABLE AUTOMATA

In [18] the last three authors introduced the notion of a generalized directable automaton as a generalization of many already known types of automata. The algorithms for testing whether a finite automaton belongs to some of important subclasses of the class of generalized directable automata are studied by the authors in [20]. In this paper structural properties of finite and infinite generalized directable automata are considered, tests for membership of a finite automaton in the pseudovarieties of generalized directable and locally directable automata are given, and the least generalized directing and locally directing congruences on a finite automaton are described.