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Symmetries of the CR sub-Laplacian
Vlasáková, Zuzana ; Souček, Vladimír (advisor) ; Slovák, Jan (referee) ; Šilhan, Josef (referee)
Title: Symmetries of the CR sub-Laplacian Author: Zuzana Vlasáková Department: Charles University Institute of Mathematics Supervisor: Prof. RNDr. Vladimír Souček, DrSc. Author's e-mail address: zuzana.kasarova@email.cz Supervisor's e-mail address: soucek@karlin.mff.cuni.cz Abstract: The aim of this work is to characterize the vector space of symme- try operators of the CR sub-Laplacian. To do this, we define a CR structure on some distinguished submanifold of Cn+1 (it is in fact the big cell in the CR sphere) and write down the CR sub-Laplacian on it. We also define the symmetries of the CR sub-Laplacian in general and using the ambient con- struction, which we introduce in the sequel, we construct all of them. Keywords: CR geometry, CR sub-Laplacian, symmetries of differential op- erator. 1
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The fields of current loops around black holes
Vlasáková, Zuzana ; Semerák, Oldřich (advisor) ; Karas, Vladimír (referee)
The field of a test current loop placed symmetrically in the equatorial plane around a Kerr black hole has been studied several times and solutions have been published in different forms. We compare these results and determine their limits in important places - in radial infinity, on the outer event horizon, on the static limit, in the equatorial plane and on the axis of symmetry. Furthermore, we show the behaviour of the field corresponding to the extreme black hole and verify Meissner effect. In the end we determine the field of a simple model of a current disc by a superposition of test current loops. This problem has an astrophysical motivation - the description of accretion discs in the vicinity of black holes. 1
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Fields of current loops around black holes
Vlasáková, Zuzana ; Semerák, Oldřich (advisor) ; Svítek, Otakar (referee)
The magnetic field of a test circular current loop placed symmetrically around a Schwarzschild black hole has been determined several times in the literature and solutions has been expressed by different formulas. We compare these formulas analytically as well as numerically, and show, in particular, how they behave on the symmetry axis, in the equatorial plane and on the horizon. The problem is relevant for modelling accretion discs around black holes.
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Linguistic Representation of the National Stereotypes in Czech Media and the Application of Cognitive Aspects in teaching Czech
Vlasáková, Zuzana ; Janovec, Ladislav (advisor) ; Chejnová, Pavla (referee) ; Holanová, Radka (referee)
Résumé This thesis under the title Linguistic Representation of National Stereotypes in Czech Media and the Application of Cognitive Aspects in Teaching Czech deals with which national stereotypes (about Romani, Vietnamese and Russians) are present in the samples selected from Czech media and how these stereotypes are linguistically represented. The paper is based on the presumption that despite the principle of political correctness present in most of the journalists' code of ethics, it is not possible to avoid some manifestations of shared fixed images of nationalities (called stereotypes) in media. Furthermore, we argue that the media image of the world is based on the Linguistic Image of the World. The theoretical basis of the cognitive linguistics, especially the Prototype/Stereotype Theory and categorization as the way of understanding and assorting the world, were the main methodological sources. There is a chapter on each analysed national group that depicts the means of its categorization and lists the particular categories that ensued from the analysis, as well as the stereotypes that were discovered in the surveyed sample. This thesis also deals with the application of aspects of cognitive linguistics in Czech language lessons (not only), as well as the possibilities of working with national...
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Linguistic Representation of National Stereotypes in Czech Media
Vlasáková, Zuzana ; Janovec, Ladislav (advisor) ; Chejnová, Pavla (referee)
Résumé This diploma thesis under the title Linguistic Representation of National Stereotypes in Czech Media deals with which stereotypes about three chosen nationalities - Romani, Vietnamese and Russians - are present in the selected sample selected from Czech media and how they are linguistically represented. The paper is based on the presumption that despite the principle of political correctness present in most of the journalese code of ethics, it is not possible to avoid some manifestations of shared fixed images of nationalities (called stereotypes) in media. Next, we argue that the media image of the world is based on the Linguistic Image of the World. The theoretical basis of the cognitive linguistics, especially the Prototype/Stereotype Theory and categorization as the way of understanding and assorting the world, were the main methodological sources. There is a chapter on each analysed national group that depicts the means of its categorisation and lists the particular categories that ensued from the analysis as well as the stereotypes that were discovered in the surveyed sample. Key words: Romani, Vietnamese, Russians, stereotypes, categorization, cognitive linguistics, media
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Symmetries of the CR sub-Laplacian
Vlasáková, Zuzana ; Souček, Vladimír (advisor) ; Slovák, Jan (referee) ; Šilhan, Josef (referee)
Title: Symmetries of the CR sub-Laplacian Author: Zuzana Vlasáková Department: Charles University Institute of Mathematics Supervisor: Prof. RNDr. Vladimír Souček, DrSc. Author's e-mail address: zuzana.kasarova@email.cz Supervisor's e-mail address: soucek@karlin.mff.cuni.cz Abstract: The aim of this work is to characterize the vector space of symme- try operators of the CR sub-Laplacian. To do this, we define a CR structure on some distinguished submanifold of Cn+1 (it is in fact the big cell in the CR sphere) and write down the CR sub-Laplacian on it. We also define the symmetries of the CR sub-Laplacian in general and using the ambient con- struction, which we introduce in the sequel, we construct all of them. Keywords: CR geometry, CR sub-Laplacian, symmetries of differential op- erator. 1
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