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A 3-dimensional graph-manifold is composed from simple blocks which are products of compact surfaces with boundary by the circle. Its global structure may be as complicated as one likes and is described by a graph which might be an…

Mathematical Physics · Physics 2007-05-23 Sergei Buyalo

In this note, we derive explicit formulae for the curvature of a convex sum of Riemannian metrics, \(g_t = (1-t)g_0 + t g_1\). We study whether such a deformation can increase the \emph{average} of the Riemann curvature component…

Differential Geometry · Mathematics 2026-05-20 Leonardo F. Cavenaghi , Giovane Galindo , Llohann D. Sperança

In this paper, we establish the existence of conformal deformations that uniformize fourth order curvature on 4-dimensional Riemannian manifolds with positive conformal invariants. Specifically, we prove that any closed, compact Riemannian…

Differential Geometry · Mathematics 2023-05-16 Sanghoon Lee

We elaborate further the $\mu$-deformation-based approach to modeling dark matter, in addition to the earlier proposed use of $\mu$-deformed thermodynamics. Herein, we construct $\mu$-deformed analogs of the Lane-Emden equation (for density…

General Physics · Physics 2020-12-03 A. M. Gavrilik , I. I. Kachurik , M. V. Khelashvili

We use certain Morse functions to construct conformal metrics with negative sectional curvature on locally conformally flat manifolds with boundary. Moreover, without conformally flatness assumption, we also construct conformal metric of…

Differential Geometry · Mathematics 2025-10-21 Rirong Yuan

The main result of this note essentially is that if the base and fibers of a compact fibration carry Hermitian metrics of positive holomorphic sectional curvature, then so does the total space of the fibration. The proof is based on the use…

Differential Geometry · Mathematics 2019-07-16 Ananya Chaturvedi , Gordon Heier

We consider curves $\gamma : [0, 1]\to\mathbb{R}^3$ endowed with an adapted orthonormal frame $r : [0, 1]\to SO(3)$. We are interested in the cases where the frame is constrained, in the sense that one of its `curvatures' (i.e.,…

Materials Science · Physics 2021-10-19 Peter Hornung

We calculate curvature tensors of metrics on the total spaces of holomorphic fibrations. Our main tool is a theory of Chern connections and curvature forms for possibly degenerate Hermitian forms on holomorphic vector bundles. We prove a…

Algebraic Geometry · Mathematics 2022-10-06 Gunnar Þór Magnússon

This work is devoted to study the deformation of spacetime metrics as generalized conformal transformations. Some applications are also considered, in particular the equations of motion in deformed spacetime are studied.

General Relativity and Quantum Cosmology · Physics 2009-11-12 D. Pugliese , C. Stornaiolo , S. Capozziello

We introduce Riemannian metrics of positive scalar curvature on manifolds with Baas-Sullivan singularities, prove a corresponding homology invariance principle and discuss admissible products. Using this theory we construct positive scalar…

Differential Geometry · Mathematics 2021-04-07 Bernhard Hanke

In this paper we investigate the curvature of conformal deformations by noncommutative Weyl factors of a flat metric on a noncommutative 2-torus, by analyzing in the framework of spectral triples functionals associated to perturbed…

Quantum Algebra · Mathematics 2013-10-15 Alain Connes , Henri Moscovici

This paper addresses Cheeger and Gromoll's question of which vector bundles admit a complete metric of nonnegative curvature, and relates their question to the issue of which sphere bundles admit a metric of positive curvature. We show that…

Differential Geometry · Mathematics 2016-09-07 Kristopher Tapp

We investigate the curvature of invariant metrics on G-manifolds with finitely many non-principal orbits. We prove existence results for metrics of positive Ricci curvature and non-negative sectional curvature, and discuss some families of…

Differential Geometry · Mathematics 2011-07-26 Stefan Bechtluft-Sachs , David J. Wraith

A consequence of the surgery theorem of Gromov and Lawson is that every closed, simply-connected 6-manifold admits a Riemannian metric of positive scalar curvature. For metrics of positive Ricci curvature it is widely open whether a similar…

Differential Geometry · Mathematics 2024-10-14 Philipp Reiser

We show that results about spaces or moduli spaces of positive scalar curvature metrics proved using index theory can typically be extended to non-negative scalar curvature metrics. We illustrate this by providing explicit generalizations…

Differential Geometry · Mathematics 2021-01-12 Thomas Schick , David J. Wraith

Any three-dimensional Riemannian metric can be locally obtained by deforming a constant curvature metric along one direction. The general interest of this result, both in geometry and physics, and related open problems are stressed.

General Relativity and Quantum Cosmology · Physics 2008-11-26 B. Coll , J. Llosa , D. Soler

We present a quantum deformation theory of the Airy curve and use it to establish a version of mirror symmetry of a point.

Algebraic Geometry · Mathematics 2014-05-22 Jian Zhou

In this paper two metric properties on geodesic length spaces are introduced by means of the metric projection, studying their validity on Alexandrov and Busemann NPC spaces. In particular, we prove that both properties characterize the…

Differential Geometry · Mathematics 2016-02-15 Alexandru Kristály , Dušan Repovš

Let $N$ be a closed enlargeable manifold in the sense of Gromov-Lawson and $M$ a closed spin manifold of equal dimension, a famous theorem of Gromov-Lawson states that the connected sum $M\# N$ admits no metric of positive scalar curvature.…

Differential Geometry · Mathematics 2017-05-25 Guangxiang Su , Weiping Zhang

We examine three-dimensional metric deformations based on a tetrad transformation through the action the matrices of scalar fields. We describe by this approach to deformation the results obtained by Coll et al. in [1], where it is stated…

General Relativity and Quantum Cosmology · Physics 2015-02-05 Daniela Pugliese , Cosimo Stornaiolo