XQuery is known to be a powerful XML query language with many bells and whistles. For many common queries we do not need all the expressive power of XQuery. We investigate the effect of omitting certain features of XQuery on the expressive power of the language. We start from a simple base fragment which can be extended by several optional features being aggregation functions such as count and ...

In this paper, we introduce a flexible consensus reaching process when agents evaluate the alternatives through linguistic expressions formed by a linguistic term, when they are confident on their opinions, or by several consecutive linguistic terms, when they hesitate. Taking into account an appropriate metric on the set of linguistic expressions and an aggregation function, a degree of consen...

We consider the problem of rewriting queries based exclusively on views. Both queries and views can contain aggregate functions and include arithmetic comparisons. To study the equivalence of a query with its rewriting query, the so called ”linearizations of a query” need to be computed. To find the linearizations of a query, the linearizations of terms from the query need to be generated. We p...

The purpose of this work is to propose a plan for future research and development of the qualitative decision support method DEX. DEX is a qualitative multi-attribute modelling method used to evaluate and analyse multiple decision alternatives in order to select the best alternative. We propose six extensions to DEX: supporting full hierarchies, using numeric attributes, probabilistic and fuzzy...

This paper examines the extent to and the conditions under which resource misallocation negatively affects aggregate productivity in a model of heterogeneous firms to the highest degree. I analytically derive the minimum aggregate total factor productivity (TFP) under resource misallocation, when frictions are modeled as the taxes levied on a firm’s output, and the range of these taxes is provi...

The paper deals with a mathematical model of a surveillance system based on a net of sensors. The signals acquired by each node of the net are Markovian process, have two different transition probabilities, which depends on the presence or absence of a intruder nearby. The detection of the transition probability change at one node should be confirmed by a detection of similar change at some oth...

The most often used operator to aggregate criteria in decision making problems is the classical weighted arithmetic mean. In many problems however, the criteria considered interact, and a substitute to the weighted arithmetic mean has to be adopted. We show that, under rather natural conditions, the discrete Choquet integral is an adequate aggregation operator that extends the weighted arithmet...

We model a competition between two teams as an all-pay auction with incomplete information. The teams may differ in size and individuals exert effort to increase the performance of one’s own team via an additively separable aggregation function. The team with a higher performance wins, and its members enjoy the prize as a public good. The value of the prize is identical to members of the same t...

The aim of this paper is to classify order-preserving functions according to their arity gap. Noteworthy examples of order-preserving functions are the so-called aggregation functions.We first explicitly classify the Lovász extensions of pseudo-Boolean functions according to their arity gap. Then we consider the class of order-preserving functions between partially ordered sets, and establish a...

The problem of extracting consistent information from relational databases violating integrity constraints on numerical data is addressed. In particular, aggregate constraints defined as linear inequalities on aggregate-sum queries on input data are considered. The notion of repair as consistent set of updates at attributevalue level is exploited, and the characterization of several complexity ...