Lietuvos matematikos rinkinys

Editorial Board and Table of Contents

2020-02-11T09:03:38+00:00

A derivation-loop method for temporal logic

2020-02-11T09:03:40+00:00

Various types of calculi (Hilbert, Gentzen sequent, resolution calculi, tableaux) for propositional linear temporal logic (PLTL) have been considered in the literature. Cutfree Gentzen-type sequent calculi are convenient tools for backward proof-search search of formulas and sequents. In this paper we present a cut-free Gentzen type sequent calculus for PLTL with the operator

Functional approach to analysis of daily tax revenues

2020-02-11T09:03:42+00:00

We present a functional data analysis approach to modeling and analyzing daily tax revenues. The main features of daily tax revenue we need to extract are some patterns within calendar months which can be used for prediction. As standard seasonal time series techniques cannot be used due to varying number of banking days per calendar month and presence of seasonality between and within months we interpret monthly tax revenues as curves obtained from daily data. Standard smoothing techniques and registration taking into account time variability are used for data preparation.

Intellectual need for mathematical knowledge

2020-02-11T09:03:39+00:00

Harel’s [2] notion of intel lectual need is refined by employing Davis’ [1] findings
about interesting propositions in social sciences. A few hypothetical examples of how this
revised definition might aid in planning mathematics lessons which provide meaningfulness
for the students are presented.

Why do we teach the mathematics that we do?

2020-02-11T09:03:37+00:00

Due to the changes of education system the school mathematics in Lithua-nia have acquired the elements of commercial-administrative mathematics of ancient times. Among other consequences the opportunities of school children to achieve the standards of mathematical reasoning are limited.

The minimizer for the second order diﬀerential problem with the integral condition

2020-02-11T09:03:42+00:00

In this paper, we investigate the best ﬁt solution for the second order diﬀerential problem with one initial and other integral conditions. We obtain the representation of that minimizer and present an example.paration.

Revised linear convolution

2020-02-11T09:03:39+00:00

It is assumed that linear time-invariant (LTI) system input signal samples are updated by a sensor in real time. It is urgent for every new input sample or for small part of new samples to update an ordinary convolution as well. The idea is that well-known convolution sum algorithm, used to calculate output signal, should not be recalculated with every new input sample. It is necessary just to modify the algorithm, when the new input sample renew the set of previous samples. Approaches in time and frequency domains are analyzed. An example of computation of the convolution in time area is presented.