Results 241 to 250 of about 3,692,977 (264)

Witten’s top Chern class via cosection localization

Inventiones Mathematicae, 2013
For a Landau–Ginzburg space $$([\mathbb {C}^n/G],W)$$([Cn/G],W), we construct Witten’s top Chern class as an algebraic cycle using cosection localized virtual cycles in the case where all sectors are narrow, verify all axioms of this class, and derive an
Huai-liang Chang, Jun Li, Wei-Ping Li
semanticscholar   +2 more sources

Second Chern class of Fano manifolds and anti-canonical geometry

Mathematische Annalen, 2017
Let X be a Fano manifold of Picard number one. We establish a lower bound for the second Chern class of X in terms of its index and degree. As an application, if Y is a n-dimensional Fano manifold with $$-K_Y=(n-3)H$$-KY=(n-3)H for some ample divisor H ...
Jie Liu
semanticscholar   +1 more source

Nef vector bundles on a projective space with first Chern class three

Rendiconti del Circolo Matematico di Palermo Series 2, 2016
We classify nef vector bundles on a projective space with first Chern class three over an algebraically closed field of characteristic zero; we see, in particular, that these nef vector bundles are globally generated if the second Chern class is less ...
M. Ohno
semanticscholar   +1 more source

Chern Classes of Representations [PDF]

Bulletin of the London Mathematical Society, 1986
For any G-module A of the group G, we have the Eilenberg-MacLane cohomology groups \(H^*(G,A)\). In general, they are quite difficult to compute. When A is the G-trivial module \({\mathbb{Z}}\), \(H^*(G,{\mathbb{Z}})\) becomes a ring, it is possible to get some information on \(H^*(G,{\mathbb{Z}})\) through the complex representation theory of G ...
openaire   +1 more source

Nef vector bundles on a projective space or a hyperquadric with the first Chern class small

Rendiconti del Circolo Matematico di Palermo Series 2, 2014
We give a new proof of the classification due to Peternell–Szurek–Wiśniewski of nef vector bundles on a projective space with the first Chern class less than three and on a smooth hyperquadric with the first Chern class less than two over an ...
M. Ohno
semanticscholar   +1 more source

Chern Class Identities from Tadpole Matching in Type IIB and F-Theory

, 2007
In light of Sen's weak coupling limit of F-theory as a type IIB orientifold, the compatibility of the tadpole conditions leads to a non-trivial identity relating the Euler characteristics of an elliptically fibered Calabi-Yau fourfold and of certain ...
P. Aluffi, M. Esole
semanticscholar   +1 more source

Comparison of the Beilinson-Chern Classes With the Chern-Cheeger-Simons Classes

1999
The Chern-Cheeger-Simons (CCS) classes of a vector bundle with connection belong to the group ofdifferential characters of[Chee-S], and depend on the choice of a connection. For a projective complex manifold, we introduce a smaller group, the group ofrestricted differential characters, which contains the CCS classes of holomorphic vector bundles ...
openaire   +2 more sources

Some Remarks on Chern Classes

The Annals of Mathematics, 1959
In this paper, we wish to study the problem of classifying all complex n-plane bundles over CW-complexes M, or equivalently, of classifying (topologically) all principal fibre bundles over M with structural group the unitary group U(n). It is well-known [6] that this set of equivalence classes is in one-to-one correspondence with the set of homotopy ...
openaire   +2 more sources

Chern classes for metacyclic groups

Archiv der Mathematik, 1993
By means of number theory arguments it is shown that the subring \(H^{\text{even}} (G,\mathbb{Z})\) of even degree classes of the integral cohomology ring \(H^*(G,\mathbb{Z})\) of a metacyclic group \(G\) is generated by Chern classes of suitable representations.
openaire   +3 more sources