Recursos de colección
In this paper we prove an equivariant version of the McKay correspondence for the elliptic genus on open varieties with a torus action. As a consequence, we will prove the equivariant DMVV formula for the Hilbert scheme of points on C2.
Cleyton, Richard; Poon, Yat-Sun
This article provides a complete description of the differential Gerstenhaber algebras of all nilpotent complex structures on any real six-dimensional nilpotent algebra. As an application, we classify all pseudo-Kählerian complex structures on six-dimensional nilpotent algebras whose differential Gerstenhaber algebra is quasi-isomorphic to that of the symplectic structure. In a weak sense of mirror symmetry, this gives a classiﬁcation of pseudo-Kähler structures on six-dimensional nilpotent algebras whose mirror images are themselves.
Qin, Zhenbo; Zhang, Qi
The Gieseker-Uhlenbeck morphism from the moduli space of Gieseker semistable rank-2 sheaves over an algebraic surface to the Uhlenbeck compactiﬁcation was constructed by Jun Li. We prove that if the anti-canonical divisor of the surface is effective and the ﬁrst Chern class of the semistable sheaves is odd, then the Gieseker-Uhlenbeck morphism is crepant
Au, Thomas Kwok-keung; Luo, Feng; Stong, Richard
In this article, we prove a theorem comparing the dihedral angles of simplexes in the hyperbolic, spherical and Euclidean geometries.
Chu, Huah; Hu, Shou-Jen; Kang, Ming-chang; Zhang, Jiping
Denote by edK(G) the essential dimension of G over K. If K is an algebraically closed ﬁeld with char K = 0, Buhler and Reichstein determine explicitly all ﬁnite groups G with edK(G) = 1. We will prove a generalization of this theorem when K is an arbitrary ﬁeld.
We prove the existence of integral canonical models of unitary Shimura varieties in arbitrary unramiﬁed mixed characteristic. Errata to [Va1] are also included.
Seshadri, Harish; Zheng, Fangyang
We show that if M = X × Y is the product of two complex manifolds (of positive dimensions), then M does not admit any complete Kähler metric with bisectional curvature bounded between two negative constants. More generally, a locally-trivial holomorphic fibre-bundle does not admit such a metric.
Lee, Jae-Hyouk; Leung, Naichung Conan
Terng, Chuu-Lian; Wang, Erxiao
We study in this note the Dirichlet problem for complex Monge-Ampère equation in compact Stein manifolds with boundary. As far as we know among the global results for Monge- Ampère equations, compact manifolds with boundary have been less discussed.
Deloup, Florian; Garber, David; Kaplan, Shmuel; Teicher, Mina
De Poi, Pietro
During the last decades, several investigations were concerned with rigidity statements for manifolds without conjugate points (some results can be found in the references). Based on an idea by E. Hopf, K. Burns and G. Knieper proved that cylinders without conjugate points and with a lower sectional curvature bound must be flat if the length of the shortest loop at every point is globally bounded. ¶ The present article reduces the last condition to a limit for the asymptotic growth of loop-length as the basepoint approaches the ends of the cylinder (Thm. 18). Along the way, the shape of cylinders without conjugate points is characterized: The loop-length...
Beffa, G. Mari
Dancer, Andrew; Swann, Andrew
A construction is introduced for modifying hyperkähler manifolds with tri-Hamiltonian circle action, that in favourable situations increases the second Betti number by one. This is based on the symplectic cut construction of Lerman. In 4 or 8 dimensions the construction may be interpreted as adding a D6-brane. A number of examples are given and a generalisation to three-Sasaki geometry discussed.
Cho, Cheol-Hyun; Oh, Yong-Geun
Eloff, Daniel; Spearman, Blair K.; Williams, Kenneth S.
An explicit integral basis is given for infinitely many cyclic quintic fields.