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Path geometries provide a geometric encoding of systems of second order ODE, which serves as a model for the geometric theory of more general systems of ODE and for cone structures. They are an instance of the family of parabolic…

Differential Geometry · Mathematics 2026-04-15 Andreas Čap , Zhangwen Guo

We use the natural lifts of the fundamental tensor field g to the cotangent bundle T*M of a Riemannian manifold (M,g), in order to construct an almost Hermitian structure (G,J) of diagonal type on T*M. The obtained almost complex structure…

Differential Geometry · Mathematics 2007-05-23 Vasile Oproiu , Dumitru Daniel Porosniuc

The characteristic connection of an almost hermitian structure is a hermitian connection with totally skew-symmetric torsion. The case of parallel torsion in dimension six is of particular interest. In this work, we give a full…

Differential Geometry · Mathematics 2009-11-13 Nils Schoemann

In this note we introduce a natural Finsler structure on convex surfaces, referred to as the projective Finsler structure, which is dual in a sense to the obvious inclusion of a convex surface in a normed space. It has an associated…

Metric Geometry · Mathematics 2011-12-02 Dmitry Faifman

In this document we present a twistor correspondence for half-flat almost-Grassmannian structures on real and complex manifolds. We provide foundational results regarding local theory in the complex setting and a global correspondence when…

Differential Geometry · Mathematics 2023-04-18 Matthew Lam

Let $(G,g)$ be a 4-dimensional Riemannian Lie group with a 2-dimensional left-invariant, conformal foliation $\F$ with minimal leaves. Let $J$ be an almost Hermitian structure on $G$ adapted to the foliation $\F$. We classify such…

Differential Geometry · Mathematics 2022-01-12 Emma Andersdotter Svensson , Sigmundur Gudmundsson

Our aim is to define and study a structure for some $(4n+3)$-dimensional manifolds which is named almost coquaternion structure. This structure is composed of three almost cocomplex structures $(\phi_a, \xi_a, \eta_a)$, $a = 1,2,3$, which…

Differential Geometry · Mathematics 2015-10-19 Constantin Udriste

A Riemannian or pseudo-Riemannian (or conformal) structure is conformally Einstein if and only if there is a suitably generic parallel section of a certain vector bundle -- the so-called standard conformal tractor bundle. We show that this…

Differential Geometry · Mathematics 2007-05-23 A. R. Gover

Consider a Grassmannian $\mathrm{Gr}(2, V)$ for an even-dimensional vector space $V$. Its derived category of coherent sheaves has a Lefschetz exceptional collection with respect to the Pl\"ucker embedding. We consider a variety $X_1$ of…

Algebraic Geometry · Mathematics 2024-07-15 Dmitrii Pirozhkov

We consider a generalization of Riemannian geometry that naturally arises in the framework of control theory. Let $X$ and $Y$ be two smooth vector fields on a two-dimensional manifold $M$. If $X$ and $Y$ are everywhere linearly independent,…

Optimization and Control · Mathematics 2007-05-23 Andrei A. Agrachev , Ugo Boscain , Mario Sigalotti

An almost-Riemannian structure on a surface is a generalized Riemannian structure whose local orthonormal frames are given by Lie bracket generating pairs of vector fields that can become collinear. The distribution generated locally by…

Differential Geometry · Mathematics 2012-03-06 Roberta Ghezzi

We study the evolution of a system of two species with nonlinear mobility and nonlocal interactions on a graph whose vertices are given by an arbitrary, positive measure. To this end, we extend a recently introduced $2$-Wasserstein-type…

Analysis of PDEs · Mathematics 2022-01-12 Georg Heinze , Jan-Frederik Pietschmann , Markus Schmidtchen

Motivated by Witten's work (arXiv:hep-th/9312104), we propose the Verlinde/Grassmannian correspondence which relates the GL Verlinde numbers to the K-theoretic quasimap invariants of the Grassmannian. We recover these two types of…

Algebraic Geometry · Mathematics 2019-07-23 Yongbin Ruan , Ming Zhang

Weyl geometry is a natural extension of conformal geometry with Weyl covariance mediated by a Weyl connection. We generalize the Fefferman-Graham (FG) ambient construction for conformal manifolds to a corresponding construction for Weyl…

High Energy Physics - Theory · Physics 2025-11-26 Weizhen Jia , Manthos Karydas , Robert G. Leigh

We provide five examples of conformal geometries which are naturally associated with ordinary differential equations (ODEs). The first example describes a one-to-one correspondence between the Wuenschmann class of 3rd order ODEs considered…

Differential Geometry · Mathematics 2009-11-10 Pawel Nurowski

Motivated by the rich geometry of conformal Riemannian manifolds and by the recent development of geometries modeled on homogeneous spaces $G/P$ with $G$ semisimple and $P$ parabolic, Weyl structures and preferred connections are introduced…

Differential Geometry · Mathematics 2007-05-23 Andreas Cap , Jan Slovak

Two-dimensional almost-Riemannian structures are generalized Riemannian structures on surfaces for which a local orthonormal frame is given by a Lie bracket generating pair of vector fields that can become collinear. We study the relation…

Differential Geometry · Mathematics 2016-11-25 Andrei Agrachev , Ugo Boscain , Grégoire Charlot , Roberta Ghezzi , Mario Sigalotti

This paper analyses the parabolic geometries generated by a free $n$-distribution in the tangent space of a manifold. It shows that certain holonomy reductions of the associated normal Tractor connections, imply preferred connections with…

Differential Geometry · Mathematics 2007-07-02 Stuart Armstrong

Recently a generalization of the Fefferman-Graham gauge for asymptotically locally AdS spacetimes, called the Weyl-Fefferman-Graham (WFG) gauge, has been proposed. It was shown that the WFG gauge induces a Weyl geometry on the conformal…

High Energy Physics - Theory · Physics 2022-10-05 Weizhen Jia , Manthos Karydas

We derive the trace and diffeomorphism anomalies of the Schr\"odinger field minimally coupled to the Newton-Cartan background using Fujikawa's path integral approach. This approach in particular enables us to calculate the one-loop…

General Relativity and Quantum Cosmology · Physics 2017-10-13 Karan Fernandes , Arpita Mitra