منابع مشابه
Derived Categories of Quadric Fibrations and Intersections of Quadrics
We construct a semiorthogonal decomposition of the derived category of coherent sheaves on a quadric fibration consisting of several copies of the derived category of the base of the fibration and the derived category of coherent sheaves of modules over the sheaf of even parts of the Clifford algebras on the base corresponding to this quadric fibration generalizing the Kapranov’s description of...
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Let k be a field of characteristic not equal to two, B a smooth projective curve of genus g(B) over k, and F its function field. A quadric hypersurface fibration is a flat projective morphism π : X → B such that each geometric fiber is a quadric hypersurface with at worst an isolated singularity and the generic fiber is smooth. Sections σ : B → X of π are in bijection with rational points X(F )...
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Assuming that φ : Sym(E) → F is a morphism of vector bundles on a variety X, we compute the class of the locus in X where Ker(φ) contains a quadric of prescribed rank. Our formulas have many applications to moduli theory: (i) we find a simple proof of Borcherds’ result that the Hodge class on the moduli space of polarized K3 surfaces of fixed genus is of Noether-Lefschetz type, (ii) we construc...
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On the category of bisimplicial sets there are different Quillen closed model structures associated to various definitions of fibrations. In one of them, which is due to Bousfield and Kan and that consists of seeing a bisimplicial set as a simplicial object in the category of simplicial sets, fibrations are those bisimplicial set maps such that each of the induced simplicial set maps is a Kan f...
متن کاملQuadric splines
Surface rendering or point location on a surface can easier be accomplished in an implicit rather than parametric representation This observation has been the key motivation for developing piecewise algebraic splines In particular Dahmen and Guo used triangular segments of quadrics to build tangent plane continuous surfaces interpolating the vertices of a trian gular net with prescribed normals...
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ژورنال
عنوان ژورنال: Journal of Algebra
سال: 2015
ISSN: 0021-8693
DOI: 10.1016/j.jalgebra.2015.06.023