https://www.journals.vu.lt/LMR/issue/feed Lietuvos matematikos rinkinys 2020-02-11T09:03:42+00:00 Remigijus Leipus remigijus.leipus@mif.vu.lt Open Journal Systems <p>Publish articles presenting new and important events in all areas of mathematics.</p> https://www.journals.vu.lt/LMR/article/view/14945 Editorial Board and Table of Contents 2020-02-11T09:03:38+00:00 Artūras Štikonas arturas.stikonas@mif.vu.lt 2019-11-13T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys https://www.journals.vu.lt/LMR/article/view/14953 A derivation-loop method for temporal logic 2020-02-11T09:03:40+00:00 Romas Alonderis romas.alonderis@mif.vu.lt Haroldas Giedra haroldas.giedra@mif.vu.lt <p><span style="background-color: #ffffff; color: #000000; font-family: &amp;quot; noto sans&amp;quot;,arial,helvetica,sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">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 </span></p> 2019-11-12T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys https://www.journals.vu.lt/LMR/article/view/14948 Functional approach to analysis of daily tax revenues 2020-02-11T09:03:42+00:00 Jovita Gudan jovita.gudan@mif.vu.lt Alfredas Račkauskas alfredas.rackauskas@mif.vu.lt <p><span style="background-color: #ffffff; color: #000000; font-family: &amp;quot; noto sans&amp;quot;,arial,helvetica,sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">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.</span></p> 2019-11-12T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys https://www.journals.vu.lt/LMR/article/view/14955 Intellectual need for mathematical knowledge 2020-02-11T09:03:39+00:00 Vytautas Miežys vytautas.miezys@mif.vu.lt <p><span style="background-color: #ffffff; color: #000000; font-family: &amp;quot; noto sans&amp;quot;,arial,helvetica,sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">Harel’s [2] notion of intel lectual need is refined by employing Davis’ [1] findings<br>about interesting propositions in social sciences. A few hypothetical examples of how this<br>revised definition might aid in planning mathematics lessons which provide meaningfulness<br>for the students are presented.</span></p> <p>&nbsp;</p> 2019-11-12T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys https://www.journals.vu.lt/LMR/article/view/14957 Why do we teach the mathematics that we do? 2020-02-11T09:03:37+00:00 Rimas Norvaiša rimas.norvaisa@mif.vu.lt <p><span style="background-color: #ffffff; color: #000000; font-family: &amp;quot; noto sans&amp;quot;,arial,helvetica,sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">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.</span></p> 2019-11-13T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys https://www.journals.vu.lt/LMR/article/view/14951 The minimizer for the second order differential problem with the integral condition 2020-02-11T09:03:42+00:00 Gailė Paukštaitė gaile.paukstaite@mif.vu.lt <p><span style="background-color: #ffffff; color: #000000; font-family: &amp;quot; noto sans&amp;quot;,arial,helvetica,sans-serif; font-size: 14px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">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.</span><span style="background-color: #ffffff;">paration.</span></p> 2019-11-12T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys https://www.journals.vu.lt/LMR/article/view/14959 Revised linear convolution 2020-02-11T09:03:39+00:00 Rimantas Pupeikis Rimantas.Pupeikis@mii.vu.lt <p><span style="background-color: #ffffff;">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.</span></p> <p>&nbsp;</p> 2019-11-12T00:00:00+00:00 Copyright (c) 2019 Lietuvos matematikos rinkinys