69 research outputs found

    Poisson-Lie T-plurality as canonical transformation

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    We generalize the prescription realizing classical Poisson-Lie T-duality as canonical transformation to Poisson-Lie T-plurality. The key ingredient is the transformation of left-invariant fields under Poisson-Lie T-plurality. Explicit formulae realizing canonical transformation are presented and the preservation of canonical Poisson brackets and Hamiltonian density is shown.Comment: 11 pages. Details of calculations added, version accepted for publicatio

    SIMD Instructions Support in LLVM Compiler

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    Tato bakalářská práce se zabývá podporou automatické vektorizace kódu v kompilačním frameworku LLVM a rozšířením modelu procesoru Codix o SIMD instrukce. Výsledkem je schopnost LLVM vytvářet reporty o proběhlém procesu autovektorizace a možnost využívat speciálních direktiv pragma pro dodání dodatečných informací pro optimalizace programů. Rovněž je představen a implementován způsob dodávání informací o architekturách procesorů vytvořených pomocí vývojového prostředí Codasip Framework, potřebných pro efektivnější vektorizaci. Nakonec je pro procesor Codix vybrána a následně do modelu přidána sada celočíselných vektorových instrukcí a souvisejících nových registrů.This bachelor thesis deals with support of automatic vectorization of code in the LLVM compilation framework and with extension of Codix processor model of SIMD instructions. As a result, LLVM is able to create reports about the process of auto-vectorization and it is possible to use special pragma directives to provide the compiler with additional information for optimizations of programs. Also a way of providing information about architectures of processors created using development environment Codasip Framework, needed for more effective vectorization, is introduced and implemented. Finally a set of integer vector instructions and related new registers for Codix is chosen and added to the model.

    Classification of Poisson-Lie T-dual models with two-dimensional targets

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    Four-dimensional Manin triples and Drinfeld doubles are classified and corresponding two-dimensional Poisson-Lie T-dual sigma models on them are constructed. The simplest example of a Drinfeld double allowing decomposition into two nontrivially different Manin triples is presented.Comment: 6 pages, LaTeX; correction: two Manin triples originally considered separately are shown to lead to the same Drinfeld doubl

    Cylindrical first order superintegrability with complex magnetic fields

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    This article is a contribution to the study of superintegrable Hamiltonian systems with magnetic fields on the three-dimensional Euclidean space E3\mathbb{E}_3 in quantum mechanics. In contrast to the growing interest in complex electromagnetic fields in the mathematical community following the experimental confirmation of its physical relevance [X. Peng et al., Phys. Rev. Lett. 114 (2015)], they were so far not addressed in the growing literature on superintegrability. Here we venture into this field by searching for additional first order integrals of motion to the integrable systems of cylindrical type. We find that already known systems can be extended into this realm by admitting complex coupling constants. In addition to them, we find one new system whose integrals of motion also feature complex constants. All these systems are multiseparable. Rigorous mathematical analysis of these systems is challenging due to the non-Hermitian setting and lost gauge invariance. We proceed formally and pose the resolution of these problems as an open challenge.Comment: The following article has been submitted to the Journal of Mathematical Physic

    Modular spaces of low-dimensional Drinfeld doubles

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    Didaktické využití vybraných anglických a českých pohádek

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    The thesis shows how the selected English fairy tales by George MacDonald (“The Light Princess”, “The Shadows”, “The Golden Key”) and selected Czech fairy tales by Karel Jaromír Erben (“Long, Broad and Sharp Eyes”, “The Firebird and Red Fox”, “Three Golden Hairs of Grandfather Know-All”) can be used in teaching English as a foreign language and Czech as a second language. Each selected fairy tale is analysed according to methodological principles and the analyses are presented in stages before, during and after reading activities. The analyses show possible activities that can be used with the selected fairy tales to promote language acquisition. Fairy tales can be used to practise all four language skills – speaking, listening, reading and writing. The selected fairy tales used here are only a suggestion and serve as examples on which possible activities are based. The choice of fairy tales and activities depends on the teacher, or more precisely, on the teacher's estimate of learners' language proficiency, needs and interests. Both cases presented in the thesis are applicable in the Croatian context due to English being taught as a foreign language in Croatian schools and Czech being taught in schools founded by the Czech minority. Besides numerous advantages of using fairy tales in teaching a language such as building vocabulary, practise reading and therefore pronunciation, there are also issues that can occur when using tales in the classroom. However they can be avoided or minimized by a good planning and organization. Alongside using fairy tales linguistically, they can be used for developing creativity and critical thinking when discussing about the issues that can be found in the text itself, such as patriarchy and murder/punishment. Despite the fact that the primary goal of using the fairy tales in language teaching is language acquisition and not critical analysis of the texts, these subliminal messages are worth addressing in the classroom and they make an excellent basis for a discussion, or more precisely, a speaking activity. All in all, using fairy tales in language teaching can be a good basis for fun activities which motivate learners and promote language acquisition.Diplomová práce ukazuje jak se vybrané anglické pohádky autora George MacDonalda (“The Light Princess”, “The Shadows”, “The Golden Key”) a vybrané české pohádky Karla Jaromíra Erbena (“Dlouhý, Široký a Bystrozraký”, “Pták Ohnivák a liška Ryška”, “Tři zlaté vlasy Děda-Vševěda”) mohou využít ve výuce anglického jako cizího a češtiny jako druhého jazyka. Každá vybraná pohádka je rozebráná podle metodických účelů a rozbor je prezentován ve fázích aktivit před četbou, během četby a po četbě. Rozbor pohádek ukazuje aktivity, jež lze využít s vybranými pohádkami pro osvojování jazyka. Rozborem pohádek je možno procvičit všechny čtyři jazykové dovednosti – mluvení, poslech, čtení a psaní. Vybrané pohádky jsou jenom návrh a příklad, jak lze aktivity organizovat. Výběr pohádek a aktivit k rozboru záleží na učiteli nebo učitelce, totiž na jejich soudu jazykových znalosti, potřeb a zájmů svých studentů. Výuka angličtiny jako cizího jazyka a češtiny jako druhého jazyka je relevantní pro Chorvatsko, jelikož se angličtina učí jako cizí jazyk na chorvatských školách a čeština se učí na školách založených českou menšinou. Kromě početných výhod, jež vyplívají z používání pohádek ve výuce jazyka, jako jsou obohacování slovníku, procvičování čtení a výslovnosti, může také dojít k různým problémům a potížím, avšak s trpělivostí a organizací se problémům může vyhnout aneb je minimalizovat. Kromĕ pro lingvistické schopnosti lze pohádky využít i pro rozvoj kreativity a kritického myšlení během diskuzí problematiky, která se může v textech objevit, jako je třeba patriarchát a vražda/trest. Navzdory tomu, že primárním cílem používání těchto pohádek ve výuce jazyka je osvojování jazyka a ne kritická analýza textů, tato neuvědomělá problematika vytváří vynikájící základ pro diskuze, respektive pro vylepšení mluvy studentů. Celkově, pohádky ve výuce jazyků mohou být výborný základ pro zajímavé aktivity, které studenty motivují a zároveň podporují osvojování jazyka

    Classification of 6-dimensional real Drinfeld doubles

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    Starting from the classification of real Manin triples done in a previous paper we look for those that are isomorphic as 6-dimensional Lie algebras with the ad-invariant form used for construction of the Manin triples. We use several invariants of the Lie algebras to distinguish the non-isomorphic structures and give explicit form of maps between Manin triples that are decompositions of isomorphic Drinfeld doubles. The result is a complete list of 6-dimensional real Drinfeld doubles. It consists of 22 classes of non-isomorphic Drinfeld doubles.Comment: 27 pages, corrected minor mistakes and typos, added reference

    Family of nonstandard integrable and superintegrable classical Hamiltonian systems in non-vanishing magnetic fields

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    In this paper we present the construction of all nonstandard integrable systems in magnetic fields whose integrals have leading order structure corresponding to the case (i) of Theorem 1 in [A Marchesiello and L \v{S}nobl 2022 {\it J. Phys. A: Math. Theor.} {\bf 55} 145203]. We find that the resulting systems can be written as one family with several parameters. For certain limits of these parameters the system belongs to intersections with already known standard systems separating in Cartesian and / or cylindrical coordinates and the number of independent integrals of motion increases, thus the system becomes minimally superintegrable. These results generalize the particular example presented in section 3 of [A Marchesiello and L \v{S}nobl 2022 {\it J. Phys. A: Math. Theor.} {\bf 55} 145203].Comment: 18 page
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