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The affine line minus one point is the underlying space of the algebraic torus of dimension one. However the fibration of an affine algebraic threefold by the affine line minus one point is not always the quotient morphism of the threefold…

Algebraic Geometry · Mathematics 2012-11-09 R. V. Gurjar , M. Koras , K. Masuda , M. Miyanishi , P. Russell

Geometrization theorem, fibered case: Every three-manifold that fibers over the circle admits a geometric decomposition. Double limit theorem: for any sequence of quasi-Fuchsian groups whose controlling pair of conformal structures tends…

Geometric Topology · Mathematics 2007-05-23 William P. Thurston

In this paper we show that for Riemannian manifolds with boundary the natural restriction map is a quasifibration between spaces of metrics of positive scalar curvature. We apply this result to study homotopy properties of spaces of such…

Geometric Topology · Mathematics 2007-05-23 Vladislav Chernysh

Generalizing the well-known Shafarevich hyperbolicity conjecture, it has been conjectured by Viehweg that a quasi-projective manifold that admits a generically finite morphism to the moduli stack of canonically polarized varieties is…

Algebraic Geometry · Mathematics 2007-07-16 Stefan Kebekus , Sandor J. Kovacs

We give sharp sectional curvature estimates for complete immersed cylindrically bounded $m$-submanifolds $\phi:M\to N\times\mathbb{R}^{\ell}$, $n+\ell\leq 2m-1$ provided that either $\phi$ is proper with the second fundamental form with…

Differential Geometry · Mathematics 2011-09-30 Luis J. Alias , G. Pacelli Bessa , J. Fabio Montenegro

Weak almost contact manifolds, i.e., the linear complex structure on the contact distribution is replaced by a nonsingular skew-symmetric tensor, defined by the author and R. Wolak, allowed us to take a new look at the theory of contact…

Differential Geometry · Mathematics 2024-10-11 Vladimir Rovenski

A compact Polish foliated space is considered. Part of this work studies coarsely quasi-isometric invariants of leaves in some residual saturated subset when the foliated space is transitive. In fact, we also use "equi-" versions of this…

Geometric Topology · Mathematics 2017-12-11 Jesús A. Álvarez López , Alberto Candel

Due to a result by Gallot a Riemannian cone over a complete Riemannian manifold is either flat or has an irreducible holonomy representation. This is false in general for indefinite cones but the structures induced on the cone by holonomy…

Differential Geometry · Mathematics 2022-04-14 Thomas Leistner

Let $M_\phi$ be a surface bundle over a circle with monodromy $\phi:S \rightarrow S$. We study deformations of certain reducible representations of $\pi_1(M_\phi)$ into $\text{SL}(n,\mathbb{C})$, obtained by composing a reducible…

Geometric Topology · Mathematics 2021-08-04 Kenji Kozai

We study analysis over infinite dimensional manifolds consisted by sequences of almost Kaehler manifolds. We develop moduli theory of pseudo holomorphic curves into such spaces with high symmetry. Many mechanisms of the standard moduli…

Symplectic Geometry · Mathematics 2012-05-15 Tsuyoshi Kato

We demonstrate the quasi-isometry invariance of two important geometric structures for relatively hyperbolic groups: the coned space and the cusped space. As applications, we produce a JSJ-decomposition for relatively hyperbolic groups…

Group Theory · Mathematics 2013-08-22 Bradley Groff

The space of the structure (0,3)-tensors of the covariant derivatives of the structure endomorphism and the metric on almost contact B-metric manifolds is considered. A known decomposition of this space in orthogonal and invariant subspaces…

Differential Geometry · Mathematics 2015-06-23 Hristo Manev

In this paper, a lot of examples of four-dimensional manifolds with an almost hypercomplex pseudo-Hermitian structure are constructed in several explicit ways. The received 4-manifolds are characterized by their linear invariants in the…

Differential Geometry · Mathematics 2012-05-08 Mancho Manev , Kouei Sekigawa

The aim of this paper is to study generalized recurrent, generalized Ricci-recurrent, weakly symmetric and weakly Ricci-symmetric Kenmotsu manifolds with respect to the semi-symmetric non-metric connection.

Differential Geometry · Mathematics 2018-01-10 S. K. Chaubey , A. C. Pandey , N. V. C. Shukla

In this paper, we study a special class of quasi-homomorphisms, i.e. quasi-retractions from a group to its subgroups. We first give some algebraic and geometric properties of quasi-retracts and then propose a theory of quasi-split short…

Group Theory · Mathematics 2025-08-21 Renxing Wan

We discuss properties of complex algebraic orbifold groups, their characteristic varieties, and their abelian covers. In particular, we deal with the question of (quasi)-projectivity of orbifold groups. We also prove a structure theorem for…

Algebraic Geometry · Mathematics 2012-03-09 Enrique Artal Bartolo , Jose Ignacio Cogolludo-Agustin , Daniel Matei

We study rational curves on general Fano hypersurfaces in projective space, mostly by degenerating the hypersurface along with its ambient projective space to reducible varieties. We prove results on existence of low-degree rational curves…

Algebraic Geometry · Mathematics 2020-03-11 Ziv Ran

The last half century of research into the structure, dynamics, and thermodynamics of simple liquids has revealed a number of approximate universalities. This paper argues that simple liquids' reduced-coordinate constant-potential-energy…

Soft Condensed Matter · Physics 2013-02-11 Jeppe C. Dyre

The fibre bundles adjoint to generalized almost quaternionic structures are studied. The most important classes of generalized almost quaternionic manifolds are considered.

dg-ga · Mathematics 2008-02-03 V. F. Kirichenko , O. E Arseneva

In this paper, we study the curve cone of an almost complex $4$-manifold which is tamed by a symplectic form. In particular, we prove the cone theorem as in Mori theory for all such manifolds using the Seiberg-Witten theory. For small…

Symplectic Geometry · Mathematics 2017-03-28 Weiyi Zhang