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For Cartan geometries admitting automorphisms with isotropies satisfying a particular, loosely dynamical property on their model geometries, we demonstrate the existence of an open subset of the geometry with trivial holonomy. This…

Differential Geometry · Mathematics 2025-04-22 Jacob W. Erickson

Let $(M,\Omega)$ be a connected symplectic 4-manifold and let $F=(J,H) : M \to \mathbb{R}^2$ be a completely integrable system on $M$ with only non-degenerate singularities and for which $J : M \to \mathbb{R}$ is a proper map. Assume that…

Mathematical Physics · Physics 2018-02-01 Holger R. Dullin , Álvaro Pelayo

Efficient real-time trajectory planning and control for fixed-wing unmanned aerial vehicles is challenging due to their non-holonomic nature, complex dynamics, and the additional uncertainties introduced by unknown aerodynamic effects. In…

In this article and its sequel we discuss the asymptotic structure of space-times representing isolated bodies in General Relativity. Such space-times are usually required to be asymptotically flat (AF), and thus to have a prescribed type…

General Relativity and Quantum Cosmology · Physics 2013-10-02 Martin Reiris

Motivated by integral point sets in the Euclidean plane, we consider integral point sets in affine planes over finite fields. An integral point set is a set of points in the affine plane $\mathbb{F}_q^2$ over a finite field $\mathbb{F}_q$,…

Combinatorics · Mathematics 2015-10-16 Michael Kiermaier , Sascha Kurz

Non-Hermitian singularities are ubiquitous in non-conservative open systems. These singularities are often points of measure zero in the eigenspectrum of the system which make them difficult to access without careful engineering. Despite…

Quantum Physics · Physics 2018-05-24 Qi Zhong , Mercedeh Khajavikhan , Demetrios Christodoulides , Ramy El-Ganainy

In general, flat outputs of a nonlinear system may depend on the system's state and input as well as on an arbitrary number of time derivatives of the latter. If a flat output which also depends on time derivatives of the input is known,…

Dynamical Systems · Mathematics 2023-01-11 Conrad Gstöttner , Bernd Kolar , Markus Schöberl

For an oriented surface $S$, the singular set of a fold map $f:S\rightarrow \mathbb{R}^2$ is a collection of smooth curves, also known as fold singularities. We construct a sharp lower bound on the number of self-intersections of such fold…

Geometric Topology · Mathematics 2026-05-14 Joshua Drouin , Liam Kahmeyer

An ideal triangulation of a singular flat surface is a geodesic triangulation such that its vertex set is equal to the set of singular points of the surface. Using the fact that each pair of points in a surface has a finite number of…

Metric Geometry · Mathematics 2020-12-01 İsmail Sağlam

In this work we show that the differential kinematics of slider-pusher systems are differentially flat assuming quasi-static behaviour and frictionless contact. Second we demonstrate that the state trajectories are invariant to…

Dynamical Systems · Mathematics 2023-02-23 Tom Lefebvre , Sander De Witte , Thomas Neve , Guillaume Crevecoeur

Motivated by integral point sets in the Euclidean plane, we consider integral point sets in affine planes over finite fields. An integral point set is a set of points in the affine plane $\mathbb{F}_q^2$ over a finite field $\mathbb{F}_q$,…

Combinatorics · Mathematics 2015-10-16 Michael Kiermaier , Sascha Kurz

We discuss integrable discretizations of 3-dimensional cyclic systems, that is, orthogonal coordinate systems with one family of circular coordinate lines. In particular, the underlying circle congruences are investigated in detail, and…

Exactly Solvable and Integrable Systems · Physics 2022-05-19 Udo Hertrich-Jeromin , Gudrun Szewieczek

Mather and Yau showed that an isolated complex hypersurface singularity is completely determined by its moduli algebra. It is shown, for the simple elliptic singularities, how to construct continuous invariants from the moduli algebras and,…

Algebraic Geometry · Mathematics 2007-05-23 Michael G. Eastwood

Harmonic coordinate conditions in stationary asymptotically flat spacetimes with matter sources have more than one solution. The solutions depend on the degree of smoothness of the metric and its first derivatives, which we wish to impose…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Jiri Bicak , Joseph Katz

In this work we study the general system of geodesic equations for the case of a massive particle moving on an arbitrary curved manifold. The investigation is carried out from the symmetry perspective. By exploiting the parametrization…

General Relativity and Quantum Cosmology · Physics 2019-06-05 N. Dimakis , Petros A. Terzis , T. Christodoulakis

The aim of this paper is to perform a deeper geometric analysis of problems appearing in dynamics of affinely rigid bodies. First of all we present a geometric interpretation of the polar and two-polar decomposition of affine motion. Later…

Mathematical Physics · Physics 2016-02-18 Jan Jerzy Sławianowski , Barbara Gołubowska , Vasyl Kovalchuk

In 1990, based on numerical and formal asymptotic analysis, Ori and Piran predicted the existence of self-similar spacetimes, called relativistic Larson-Penston solutions, that can be suitably flattened to obtain examples of spacetimes that…

Analysis of PDEs · Mathematics 2021-12-22 Yan Guo , Mahir Hadzic , Juhi Jang

Numerical stability is of great significance for discrete-time dynamic vehicle model. Among the unstable factors, low-speed singularity stands out as one of the most challenging issues, which arises from that the denominator of tire side…

Systems and Control · Electrical Eng. & Systems 2024-11-27 Guojian Zhan , Qiang Ge , Haoyu Gao , Yuming Yin , Bin Zhao , Shengbo Eben Li

Constraining motion to a flat surface is a fundamental requirement for equipment across science and engineering. Modern precision robotic motion systems, such as gantries, rely on the flatness of components, including guide rails and…

As a core part of autonomous driving systems, motion planning has received extensive attention from academia and industry. However, real-time trajectory planning capable of spatial-temporal joint optimization is challenged by nonholonomic…

Robotics · Computer Science 2023-04-11 Zhichao Han , Yuwei Wu , Tong Li , Lu Zhang , Liuao Pei , Long Xu , Chengyang Li , Changjia Ma , Chao Xu , Shaojie Shen , Fei Gao