Říká se, že jedním ze znaků správné fyzikální teorie je její krása. Máme-li na mysli estetičnost matematickou, patří variační počet k matematickým metodám, které naplňují tento požadavek vrchovatě. Je také pravda, že správné (zkušeností a experimentem prověřené) fyzikální teorie bývají variační, tj. odvoditelné z variačního principu: Klasická mechanika, relativistická mechanika, kvantová mechanika, klasická elektrodynamika... Na zcela elementární úrovni předkládáme základní myšlenku a klasické postupy variačního počtu, s ukázkami použití v geometrii a fyzice. Zaměříme se pouze na variační princip prvního řádu, s důrazem na mechaniku, kde na rozdíl od teorie pole závisí řešené úlohy pouze na jedné nezávisle proměnné, ve fyzice obvykle na čase., It is said that one of the characteristic features of physical theories is their beauty. Having in mind the "mathematical aesthetic appearance" one can say that the calculus of variations highly fulfils this requirement! It is also well known that correct physical theories (those verified experimentally), are often variational, i.e. based on a variational principle: classical mechanics, relativistic mechanics, quantum mechanics, classical electrodynamics, etc. We present, at a very basic level, the fundamental ideas and classical approaches of the calculus of variations, including examples of their use in geometry and physics. We focus on the first order variational principle, emphasizing mechanics, because contrary to field theories, the variational problems in mechanics depend on one independent variable only (usually time in physics)., Jana Musilová, Pavla Musilová., and Obsahuje bibliografii
The aim of the article is to present an analysis of variant endings -i and -é. The research was carried out on the base of Czech National Corpus SYN2005. The ending -i is a variant of ending -é in the standard language (it amounts to 4 %). According to the corpora examination, the ending -i can be mainly found in the names of followers and members of social and political movements and institutions. No occurence or sporadic occurrence of the ending -i can be found in names of followers of religious views, suppor-ters of religious movements and members of sects, the names of specialists and sportsmen. The occurence of the form -i depends on the various factors: linguistical layer, semantical group that the word belongs to, type and frequency of the word, context and a text.
Preliminary results of a search for the variation of the solar granulation properties with the heliographic laitude are presented. Within errors, no changes are found in the power spectra and sizes between N-S and E-W scans.
The presented article examines the early medieval settlement in Brno- -Medlánky. The archaeological finds were evaluated to obtain settlement spatial development and to reveal the practical, social and natural dimension of the settlement after the synthesis of the evidence. The relevance of the site in relation to early medieval Brno was also considered. The large quantity of ceramics, which was essential for this research, was processed using the database of J. Macháček. This enabled me to date the settlement between the 6th/7th to the 9th/10th century and, based on quantification, to characterise the morphological and technological features of the complex. The archaeological material was also compared with the material from other similar sites. The results of this analysis were acquired from data in the graphs, figures and quantification tables. The other findings were processed using descriptive models. Scientific analyses have proven the presence of blacksmithing and iron metallurgy at the site. Agricultural activities and processing of leather and textile were also documented at the site. The typical cumulative structure was evaluated within the framework of spatial analyses, together with the form and spatial development of the settlement. Moreover, the article deals with the complete skeletons of two dogs and one horse, and the human skeleton found in a storage pit. The complete animal skeletons were probably deposited for hygienic reasons; the human skeleton possibly proves an execution.
napsal Matěj Hlinecký, Poznámky pod čarou, Obsahuje bibliografii a bibliografické odkazy, and Converted from MODS to DC version 1.8 (EE patch 2018/05/24)