Lietuvos matematikos rinkinys <p>Publish articles presenting new and important events in all areas of mathematics.</p> lt-LT <p>Please read the Copyright Notice in&nbsp;<a href="">Journal Policy</a>.&nbsp;</p> (Remigijus Leipus) (Vigintas Stancelis) Thu, 18 Feb 2021 14:42:31 +0000 OJS 60 Editorial Board and Table of Contents Copyright (c) 2020 Lietuvos matematikos rinkinys Thu, 18 Feb 2021 00:00:00 +0000 Relations between spectrum curves of discrete Sturm-Liouville problem with nonlocal boundary conditions and graph theory <p>Sturm-Liouville problem with nonlocal boundary conditions arises in many scientific fields such as chemistry, physics, or biology. There could be found some references to graph theory in a discrete Sturm-Liouville problem, especially in investigation of spectrum curves. In this paper, relations between discrete Sturm-Liouville problem with nonlocal boundary conditions characteristics (poles, critical points, spectrum curves) and graphs characteristics (vertices, edges and faces) were found.</p> Jonas Vitkauskas | Artūras Štikonas Copyright (c) 2020 Lietuvos matematikos rinkinys Thu, 18 Feb 2021 00:00:00 +0000 Effective bounds of the variance of statistics on multisets of necklaces <p>The variance of a linear statistics on multisets of necklaces is explored. The upper and lower bounds with optimal constants are obtained</p> Arvydas Karbonskis | Eugenijus Manstavičius Copyright (c) 2020 Lietuvos matematikos rinkinys Thu, 18 Feb 2021 00:00:00 +0000 The stability analysis of the market price using Lambert function method <p>In this article we are going to analyze market price stability with different market intensity coefficient and delay argument values. Market price is described as a scalar differential equation with a delay argument. In order to find solutions for the transcendental equation we will use method based on Lambert function. We will present examples of the applications of the method.</p> Irma Jankauskienė | Tomas Miliūnas Copyright (c) 2020 Lietuvos matematikos rinkinys Thu, 18 Feb 2021 00:00:00 +0000 On a classification of word problems from the first grade Lithuanian textbooks <p>Word problems are classified to S problems and P problems by Verschaffel [9], classification is being specified and expanded. Reviewed word problems in Lithuanian first grade textbooks and divided to types. Submitted recommendations to use more varied types word problems, that would let to expand concepts understanding, develop mathematical reasoning, motivate to study word problem.</p> <div class="ms-editor-squiggler" style="color: initial; font: initial; font-feature-settings: initial; font-kerning: initial; font-optical-sizing: initial; font-variation-settings: initial; forced-color-adjust: initial; text-orientation: initial; text-rendering: initial; -webkit-font-smoothing: initial; -webkit-locale: initial; -webkit-text-orientation: initial; -webkit-writing-mode: initial; writing-mode: initial; zoom: initial; place-content: initial; place-items: initial; place-self: initial; alignment-baseline: initial; animation: initial; appearance: initial; aspect-ratio: initial; backdrop-filter: initial; backface-visibility: initial; background: initial; background-blend-mode: initial; baseline-shift: initial; block-size: initial; border-block: initial; border: initial; border-radius: initial; border-collapse: initial; 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padding-inline: initial; page: initial; page-orientation: initial; paint-order: initial; perspective: initial; perspective-origin: initial; pointer-events: initial; position: initial; quotes: initial; r: initial; resize: initial; ruby-position: initial; rx: initial; ry: initial; scroll-behavior: initial; scroll-margin-block: initial; scroll-margin: initial; scroll-margin-inline: initial; scroll-padding-block: initial; scroll-padding: initial; scroll-padding-inline: initial; scroll-snap-align: initial; scroll-snap-stop: initial; scroll-snap-type: initial; shape-image-threshold: initial; shape-margin: initial; shape-outside: initial; shape-rendering: initial; size: initial; speak: initial; stop-color: initial; stop-opacity: initial; stroke: initial; stroke-dasharray: initial; stroke-dashoffset: initial; stroke-linecap: initial; stroke-linejoin: initial; stroke-miterlimit: initial; stroke-opacity: initial; stroke-width: initial; tab-size: initial; table-layout: initial; text-align: initial; text-align-last: initial; text-anchor: initial; text-combine-upright: initial; text-decoration: initial; text-decoration-skip-ink: initial; text-indent: initial; text-overflow: initial; text-shadow: initial; text-size-adjust: initial; text-transform: initial; text-underline-offset: initial; text-underline-position: initial; touch-action: initial; transform: initial; transform-box: initial; transform-origin: initial; transform-style: initial; transition: initial; user-select: initial; vector-effect: initial; vertical-align: initial; visibility: initial; -webkit-app-region: initial; border-spacing: initial; -webkit-border-image: initial; -webkit-box-align: initial; -webkit-box-decoration-break: initial; -webkit-box-direction: initial; -webkit-box-flex: initial; -webkit-box-ordinal-group: initial; -webkit-box-orient: initial; -webkit-box-pack: initial; -webkit-box-reflect: initial; -webkit-highlight: initial; -webkit-hyphenate-character: initial; -webkit-line-break: initial; -webkit-line-clamp: initial; -webkit-mask-box-image: initial; -webkit-mask: initial; -webkit-mask-composite: initial; -webkit-perspective-origin-x: initial; -webkit-perspective-origin-y: initial; -webkit-print-color-adjust: initial; -webkit-rtl-ordering: initial; -webkit-ruby-position: initial; -webkit-tap-highlight-color: initial; -webkit-text-combine: initial; -webkit-text-decorations-in-effect: initial; -webkit-text-emphasis: initial; -webkit-text-emphasis-position: initial; -webkit-text-fill-color: initial; -webkit-text-security: initial; -webkit-text-stroke: initial; -webkit-transform-origin-x: initial; -webkit-transform-origin-y: initial; -webkit-transform-origin-z: initial; -webkit-user-drag: initial; -webkit-user-modify: initial; white-space: initial; widows: initial; width: initial; will-change: initial; word-break: initial; word-spacing: initial; x: initial; y: initial; z-index: initial;">&nbsp;</div> Ieva Kilienė Copyright (c) 2020 Lietuvos matematikos rinkinys Mon, 01 Mar 2021 00:00:00 +0000 Models of virtual library users’ behavior analysis <p>In this paper, we present models for the analysis of the behavior of the virtual library (VL) users. Unlike the models presented in the literature,&nbsp; they use only the big data that is stored in the log files of virtual library servers and methods of statistics, association rules, and recommendation systems. The proposed models were implemented with R software. Using the proposed models,&nbsp; the analysis of the behavior of VL users of Lithuanian research and study of higher education institutions was performed for the first time. The results&nbsp; showed that the proposed models allow to operatively analyze the behavior of virtual library users using advanced search filters, facets, and provide suggestions for improvement of service quality.</p> Gytis Vievesis | Vytautas Janilionis | Antanas Štreimikis Copyright (c) 2021 Lietuvos matematikos rinkinys Thu, 18 Feb 2021 00:00:00 +0000