منابع مشابه
Topology of Blow–ups and Enumerative Geometry
Let f M be the blow–up of a complex manifold M along a submanifold X. We determine the integral cohomology ring and obtain a formula for the Chern classes of f M . As applications we determine the cohomology rings for the varieties of complete conics and complete quadrices in 3–space, and justify two enumerative results due to Schubert [S1, §20; §22]. 2000 Mathematical Subject Classification: 1...
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Consider the following situation: MC is a complex manifold of complex dimension n, and DC is a union of smooth complex codimension-one submanifolds (i.e., DC is a smooth divisor). Examples of this situation include: (1) arrangements of projective hyperplanes in CP, as well as various blow-ups of such arrangements along intersections of hyperplanes, (2) nonsingular toric varieties (whereDC is th...
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A conjecture on vanishing and non-negativity of intersection multiplicity on the blow-up of a regular local ring at its closed point has been proposed. Proofs of vanishing, several special cases of non-negativity and a sufficient condition for non-negativity of this conjecture are described. The topic on intersection multiplicity on vector bundles is also addressed. Introduction. Let X be a reg...
متن کاملChern Classes of Blow-ups
We extend the classical formula of Porteous for blowing-up Chern classes to the case of blow-ups of possibly singular varieties along regularly embedded centers. The proof of this generalization is perhaps conceptually simpler than the standard argument for the nonsingular case, involving Riemann-Roch without denominators. The new approach relies on the explicit computation of an ideal, and a m...
متن کاملGeneralized complex geometry
Generalized complex geometry encompasses complex and symplectic geometry as its extremal special cases. We explore the basic properties of this geometry, including its enhanced symmetry group, elliptic deformation theory, relation to Poisson geometry, and local structure theory. We also define and study generalized complex branes, which interpolate between flat bundles on Lagrangian submanifold...
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ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 2018
ISSN: 0002-9947,1088-6850
DOI: 10.1090/tran/7412