977 research outputs found

    An analogue of the Narasimhan-Seshadri theorem and some applications

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    We prove an analogue in higher dimensions of the classical Narasimhan-Seshadri theorem for strongly stable vector bundles of degree 0 on a smooth projective variety XX with a fixed ample line bundle Θ\Theta. As applications, over fields of characteristic zero, we give a new proof of the main theorem in a recent paper of Balaji and Koll\'ar and derive an effective version of this theorem; over uncountable fields of positive characteristics, if GG is a simple and simply connected algebraic group and the characteristic of the field is bigger than the Coxeter index of GG, we prove the existence of strongly stable principal GG bundles on smooth projective surfaces whose holonomy group is the whole of GG.Comment: 42 pages. Theorem 3 of this version is new. Typos have been corrected. To appear in Journal of Topolog

    Tensor product theorem for Hitchin pairs -An algebraic approach

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    We give an algebraic approach to the study of Hitchin pairs and prove the tensor product theorem for Higgs semistable Hitchin pairs over smooth projective curves defined over algebraically closed fields kk of characteristic 00 and characteristic pp, with pp satisfying some natural bounds. We also prove the corresponding theorem for polystable bundles.Comment: To appear in Annales de l'Institut Fourier, Volume 61 (2011

    Aerodynamic Parameter Estimation From Flight Data Of The Unconventional Aircraft

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    This Document Gives Complete Results Of Parameter Estimation From Flight Data Of The Unconventional Aircraft. It Also Includes The Results Of Handling Quality Evaluation Based On Linear Estimated Models From Flight Data And Simulation Model Validation

    Simulation Modeling Of A Transport Aircraft Using Flight Test Data

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    The Mathematical Models Using Flight Test Data With Respect To A Transport. Aircraft For The Offline Simulation Are Described In This Document. For The Purpose Of Simulation Validation Process, Representative Flight Data Sets Are Selected From A Data Bank Which Was Created Previously Using Data From Actual Flight Maneuvers

    Catalysis of Flavor Nonconservation by Monopoles

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    A simple argument based on current algebra is given to show how monopoles can lead to baryon decay and other flavor-changing processes

    Second-order Phase Transitions, Inflationary Universe, and Formation of Galaxies

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    At the critical point of a second-order phase transition, statistical fluctuations are correlated and enhanced in amplitude. We explore this phenomenon in the early universe as a possible mechanism for the formation of galaxies. In an inflationary universe, such dynamical effects on galactic scales are consistent with the constraints imposed by the horizon. Spontaneous breakdown of lepton number provides a model where these ideas are realized. The two-point correlation function for density fluctuations is calculated and agrees with the observed correlation for galaxies. An estimate of the density contrast is shown to be of the required magnitude

    Orientation Dependence of Elastic Constants for Ice

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    Orientation dependence of Young's and shear moduli of ice single crystals has been calculated at various temperatures using the most up-to-date values of elastic constants and classical equations derived for hexagonal materials. Young's modulus is a maximum whereas shear modulus has a minimum value along the c-axis. Along a direction 50 degree to the c-axis, the shear modulus has a maximum value and the Young's modulus, a minimum. Average values of polycrystal moduli calculated from single crystal values showed only mild temperature dependence
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