5,187 research outputs found

    Relaxation to magnetohydrodynamics equilibria via collision brackets

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    Metriplectic dynamics is applied to compute equilibria of fluid dynamical systems. The result is a relaxation method in which Hamiltonian dynamics (symplectic structure) is combined with dissipative mechanisms (metric structure) that relaxes the system to the desired equilibrium point. The specific metric operator, which is considered in this work, is formally analogous to the Landau collision operator. These ideas are illustrated by means of case studies. The considered physical models are the Euler equations in vorticity form, the Grad-Shafranov equation, and force-free MHD equilibria.Comment: Conference Proceeding (Theory of Fusions Plasmas, 2018), 9 pages, 8 figure

    Ksenologia i ksenotopografia Bernharda Waldenfelsa wobec podstawowych założeń światotwórczych literatury fantastycznej (Orson Scott Card, Neil Gaiman, George R. R. Martin)

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    XENOLOGY AND XENOTOPOGRAPHY OF BERNHARD WALDENFELS The paper strives to adapt Bernhard Waldenfels’ xenology and so called ‘xenotopography’ for the philosophico-literary studies in fantastic world-building with a special concern of the ‘portal-quest’ model of fantasy and SF. Following Waldenfel’s remarks on the nature of post- Husserlian diastasis of our world [Heimwelt] and otherworld [Fremdwelt] and acknowledging the consequences of allocating one’s attitude towards the otherness in the symbolical borderland [‘sphere of intermonde’] in between, it is examined whether such a model can occur in the fantastic literature and what may be the consequence of xenotopographic reconsideration of its basic ontological premises. Additionally, the article offers an original xenotopograpfic model of worldbuilding which addresses three carefully chosen case studies of fantastic worlds from Orson Scott Card’s Ender’s Game tetralogy, Neil Gaiman’s Stardust and George R. R. Martin’s The Song of Ice and Fire. In the end, it is suggested that hitherto presented xenotopography gravely inspired a postmodern shift in the genres of fantasy and SF which results in more ethically conscious representations of the otherness and even more concise and alien comprehensive world-building

    Groza systemowej niewiedzy. O dystopijnej rzeczywistości "Przeglądu Końca Świata" Miry Grant

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    In the chapter Horror of the Systemic Unawareness. On A Dystopian Reality of Mira Grant’s “Newslfesh” Krzysztof M. Maj invites a Foucauldian reading of the epony-mous fear of being unaware of the truth about the “founding lie” of dystopian socio-stasis. While doing so, he proceeds with an analysis of the basic components of dysto-pian narrative, pondering on the subtle relationships between the so-called young adult dystopias, postapocalyptic lore, and “political technology of the body”—with the latter being an ultimate tool of authoritatian control observed in Newsflesh trilogy. Simultaneously, the chapter serves as a concise introduction to contemporary world-centered dystopian narratives, greatly inspired by a deconstructive approach to utopian and dystopian studies, with a particular emphasis on the subversion of metaphysical paradigms and binary oppositions, critique of logocentrism and panopticism, or dis-semination of power/knowledge. Finally, Maj argues that the state of unawareness may be both a curse and a blessing in a dystopian reality—a curse, as it strikes fear into the hearts of subdued citizens who learn thereby to be afraid of any rebellious activities, and a blessing, as it may inspire a strong individual to overcome their fear and challenge the reign of oppressive authorities.Krzysztof M. Ma

    Written on the tragic death not a solider in Germany

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    A generalization to Sylow permutability of pronormal subgroups of finite groups

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    Electronic version of an article published as Journal of Algebra and Its Applications, 2020, 19:03 https://doi.org/10.1142/S0219498820500528 © World Scientific Publishing Company.[EN] In this note, we present a new subgroup embedding property that can be considered as an analogue of pronormality in the scope of permutability and Sylow permutability in finite groups. We prove that finite PST-groups, or groups in which Sylow permutability is a transitive relation, can be characterized in terms of this property, in a similar way as T-groups, or groups in which normality is transitive, can be characterized in terms of pronormality.The research of the first author has been supported by the research grants MTM2014-54707-C3-1-P by the "Ministerio de Economia y Competitividad" (Spain) and FEDER (European Union) and PROMETEO/2017/057 from "Generalitat" (Valencian Community, Spain). Part of the work of this paper has been done during some visits of the first author to the Dipartimento di Matematica of the Universita degli Studi di Salerno supported by the "National Group for Algebraic and Geometric Structures, and their Applications" (GNSAGA - INdAM), Italy.Esteban Romero, R.; Longobardi, P.; Maj, M. (2020). A generalization to Sylow permutability of pronormal subgroups of finite groups. Journal of Algebra and Its Applications. 19(3):1-13. https://doi.org/10.1142/S0219498820500528S113193Ballester-Bolinches, A., & Esteban-Romero, R. (2002). Sylow Permutable Subnormal Subgroups of Finite Groups. Journal of Algebra, 251(2), 727-738. doi:10.1006/jabr.2001.9138Ballester-Bolinches, A., & Esteban-Romero, R. (2003). On finite J-groups. Journal of the Australian Mathematical Society, 75(2), 181-192. doi:10.1017/s1446788700003712Ballester-Bolinches, A., & Esteban-Romero, R. (2003). On finite soluble groups in which Sylow permutability is a transitive relation. Acta Mathematica Hungarica, 101(3), 193-202. doi:10.1023/b:amhu.0000003903.71033.fcBallester-Bolinches, A., Esteban-Romero, R., & Asaad, M. (2010). Products of Finite Groups. de Gruyter Expositions in Mathematics. doi:10.1515/9783110220612Ballester-Bolinches, A., Feldman, A. D., Pedraza-Aguilera, M. C., & Ragland, M. F. (2011). A class of generalised finite T-groups. Journal of Algebra, 333(1), 128-138. doi:10.1016/j.jalgebra.2011.02.018Deskins, W. E. (1963). On quasinormal subgroups of finite groups. Mathematische Zeitschrift, 82(2), 125-132. doi:10.1007/bf01111801Doerk, K., & Hawkes, T. O. (1992). Finite Soluble Groups. doi:10.1515/9783110870138Huppert, B. (1967). Endliche Gruppen I. Grundlehren der mathematischen Wissenschaften. doi:10.1007/978-3-642-64981-3Kaplan, G. (2010). On T-groups, supersolvable groups, and maximal subgroups. Archiv der Mathematik, 96(1), 19-25. doi:10.1007/s00013-010-0207-0Kegel, O. H. (1962). Sylow-Gruppen und Subnormalteiler endlicher Gruppen. Mathematische Zeitschrift, 78(1), 205-221. doi:10.1007/bf01195169Mysovskikh, V. I. (1999). Investigation of Subgroup Embeddings by the Computer Algebra Package GAP. Computer Algebra in Scientific Computing CASC’99, 309-315. doi:10.1007/978-3-642-60218-4_24Peng, T. A. (1969). Finite groups with pro-normal subgroups. Proceedings of the American Mathematical Society, 20(1), 232-232. doi:10.1090/s0002-9939-1969-0232850-1Peng, T. A. (1971). Pronormality in Finite Groups. Journal of the London Mathematical Society, s2-3(2), 301-306. doi:10.1112/jlms/s2-3.2.301Schmid, P. (1998). Subgroups Permutable with All Sylow Subgroups. Journal of Algebra, 207(1), 285-293. doi:10.1006/jabr.1998.7429Wielandt, H. (1939). Eine Verallgemeinerung der invarianten Untergruppen. Mathematische Zeitschrift, 45(1), 209-244. doi:10.1007/bf01580283Yi, X., & Skiba, A. N. (2014). On SS S -propermutable Subgroups of Finite Groups. Bulletin of the Malaysian Mathematical Sciences Society, 38(2), 605-616. doi:10.1007/s40840-014-0038-
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