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In this paper we study the invariant Walker structures over the conformally flat four-dimensional homogeneous manifolds according to the Seger types of the Ricci operator.

Differential Geometry · Mathematics 2015-01-13 M. Chaichi , A. Zaeim , Y. Keshavarzi

We present a survey on 4D generation and reconstruction, a fast-evolving subfield of computer graphics whose developments have been propelled by recent advances in neural fields, geometric and motion deep learning, as well as 3D generative…

Computer Vision and Pattern Recognition · Computer Science 2026-03-10 Mingrui Zhao , Sauradip Nag , Kai Wang , Aditya Vora , Guangda Ji , Peter Chun , Ali Mahdavi-Amiri , Hao Zhang

In recent years there has been a lot of interest in discussing frame dependences/independences of the cosmological perturbations under the conformal transformations. This problem has previously been investigated in terms of the covariant…

General Relativity and Quantum Cosmology · Physics 2018-03-14 Yunlong Zheng , Yicen Mou , Haomin Rao , Mingzhe Li

We compute the oriented cobordism group of fold maps of 4-manifolds into the space with all the possible restrictions (and also with no restriction) to the singular fibers. We also give geometric invariants which describe completely the…

Geometric Topology · Mathematics 2008-05-12 Boldizsar Kalmar

This note discusses recent new approaches to studying flopping curves on 3-folds. In a joint paper, the author and Michael Wemyss introduced a 3-fold invariant, the contraction algebra, which may be associated to such curves. It…

Algebraic Geometry · Mathematics 2015-11-06 Will Donovan

In this article, we study the invariant differential forms which a correspondence of curves admits. We also try to classify the correspondences of $\mathbb{P}^1$ that admits such invariant differential forms.

Algebraic Geometry · Mathematics 2012-03-07 Arnab Saha

The class of the hypercomplex pseudo-Hermitian manifolds is considered. The flatness of the considered manifolds with the 3 parallel complex structures is proved. Conformal transformations of the metrics are introduced. The conformal…

Differential Geometry · Mathematics 2012-03-27 Kostadin Gribachev , Mancho Manev , Stancho Dimiev

We define and study complex structures and generalizations on spaces consisting of geodesics or harmonic maps that are compatible with the symmetries of these spaces. The main results are about existence and uniqueness of such structures.

Differential Geometry · Mathematics 2019-01-14 László Lempert

We introduce the concept of bi-conformal transformation, as a generalization of conformal ones, by allowing two orthogonal parts of a manifold with metric $\G$ to be scaled by different conformal factors. In particular, we study their…

Mathematical Physics · Physics 2016-08-16 Alfonso García-Parrado , José M. M. Senovilla

This manuscript develops a geometric approach to ordinary cohomology of smooth manifolds, constructing a cochain complex model based on co-oriented smooth maps from manifolds with corners. Special attention is given to the pull-back product…

Algebraic Topology · Mathematics 2026-05-01 Greg Friedman , Anibal M. Medina-Mardones , Dev Sinha

Hypersurfaces embedded in conformal manifolds appear frequently as boundary data in boundary-value problems in cosmology and string theory. Viewed as the non-null conformal infinity of a spacetime, we consider hypersurfaces embedded in a…

Differential Geometry · Mathematics 2023-02-06 Samuel Blitz

This gives some information about the conformal point and the calibrating conic, and their relationship one to the other. These concepts are useful for visualizing image geometry, and lead to intuitive ways to compute geometry, such as…

Computer Vision and Pattern Recognition · Computer Science 2026-01-21 Richard Hartley

This paper defines two new extrinsic curvature quantities on the corner of a four-dimensional Riemannian manifold with corner. One of these is a pointwise conformal invariant, and the conformal transformation of the other is governed by a…

Differential Geometry · Mathematics 2021-11-10 Stephen E. McKeown

Shape analysis and compuational anatomy both make use of sophisticated tools from infinite-dimensional differential manifolds and Riemannian geometry on spaces of functions. While comprehensive references for the mathematical foundations…

Differential Geometry · Mathematics 2018-07-31 Martins Bruveris

This PhD dissertation is concerned with integral geometric inverse problems. The geodesic ray transform is an operator that encodes the line integrals of a function along geodesics. The dissertation establishes many conditions when such…

Differential Geometry · Mathematics 2020-10-23 Jesse Railo

Despite spectacular advances in defining invariants for simply connected smooth and symplectic 4-dimensional manifolds and the discovery of effective surgical techniques, we still have been unable to classify simply connected smooth…

Geometric Topology · Mathematics 2007-05-23 Ronald Fintushel , Ronald J. Stern

With the advancement of computer technology, there is a surge of interest in effective mapping methods for objects in higher-dimensional spaces. To establish a one-to-one correspondence between objects, higher-dimensional quasi-conformal…

Computational Geometry · Computer Science 2022-06-30 Daoping Zhang , Gary P. T. Choi , Jianping Zhang , Lok Ming Lui

Biconformal deformations take place in the presence of a conformal foliation, deforming by different factors tangent to and orthogonal to the foliation. Four-manifolds endowed with a conformal foliation by surfaces present a natural context…

Differential Geometry · Mathematics 2021-05-11 Paul Baird , Jade Ventura

We compute the dynamical degrees of certain compositions of reflections in points on a smooth cubic fourfold. Our interest in these computations stems from the irrationality problem for cubic fourfolds. Namely, we hope that they will…

Algebraic Geometry · Mathematics 2017-09-21 Christian Böhning , Hans-Christian Graf von Bothmer , Pawel Sosna

Minimal surfaces are among the most natural objects in Differential Geometry, and have been studied for the past 250 years ever since the pioneering work of Lagrange. The subject is characterized by a profound beauty, but perhaps even more…

Differential Geometry · Mathematics 2014-09-29 Fernando Coda Marques