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We develop a notion of rank one properly convex domains (or Hilbert geometries) in the real projective space. This is in the spirit of rank one non-positively curved Riemannian manifolds and CAT(0) spaces. We define rank one isometries for…

Geometric Topology · Mathematics 2025-06-11 Mitul Islam

In this paper we develop general formulas for the subdifferential of the pointwise supremum of convex functions, which cover and unify both the compact continuous and the non-compact non-continuous settings. From the non-continuous to the…

Optimization and Control · Mathematics 2020-04-03 Rafael Correa , Abderrahim Hantoute , Marco Antonio López

For a strictly convex set $K\subset \mathbb{R}^2$ of class $C^2$ we consider its associated sub-Finsler $K$-perimeter $|\partial E|_K$ in $\mathbb{H}^1$ and the prescribed mean curvature functional $|\partial E|_K-\int_E f$ associated to a…

Differential Geometry · Mathematics 2021-12-22 Gianmarco Giovannardi , Manuel Ritoré

We give a new approach to the infinitesimal structure of Lipschitz maps into L^1. As a first application, we give an alternative proof of the main theorem from an earlier paper, that the Heisenberg group does not admit a bi-Lipschitz…

Metric Geometry · Mathematics 2015-05-13 Jeff Cheeger , Bruce Kleiner

Let $H$ and $G$ be two finite graphs. Define $h_H(G)$ to be the number of homomorphisms from $H$ to $G$. The function $h_H(\cdot)$ extends in a natural way to a function from the set of symmetric matrices to $\mathbb{R}$ such that for…

Functional Analysis · Mathematics 2008-06-03 Hamed Hatami

Let $H$ be a normal subgroup of a group $G$. The normal subgroup based power graph $\Gamma_H(G)$ of $G$ is the simple undirected graph with vertex set $V(\Gamma_H(G))= (G\setminus H)\cup \{e\}$ and two distinct vertices $a$ and $b$ are…

Combinatorics · Mathematics 2024-04-08 Parveen , Manisha , Jitender Kumar

The bracket map was originally considered for locally compact abelian groups. In this work we extend the study of bracket maps to the noncommutative setting, providing characterizations of bases and frames for cyclic subspaces of the…

Functional Analysis · Mathematics 2013-03-12 Davide Barbieri , Eugenio Hernandez , Azita Mayeli

The paper is devoted to a comprehensive second-order study of a remarkable class of convex extended-real-valued functions that is highly important in many aspects of nonlinear and variational analysis, specifically those related to…

Optimization and Control · Mathematics 2015-07-21 Boris S. Mordukhovich , M. Ebrahim Sarabi

We discuss a variational approach to the length functional and its relation to sub-Hamiltonian equations on sub-Finsler manifolds. Then, we introduce the notion of the nonholonomic sub-Finslerian structure and prove that the distributions…

Differential Geometry · Mathematics 2025-07-14 Layth M. Alabdulsada

We study the geodesic flow corresponding to the left-invariant sub-Riemannian metric and the right-invariant distribution on the second Heisenberg group. The corresponding Hamiltonian system is completely integrable and in this paper we…

Differential Geometry · Mathematics 2026-05-06 Milan Pavlović

We consider semidifferentiable (possibly nonsmooth) maps, acting on a subset of a Banach space, that are nonexpansive either in the norm of the space or in the Hilbert's or Thompson's metric inherited from a convex cone. We show that the…

Functional Analysis · Mathematics 2014-03-12 Marianne Akian , Stephane Gaubert , Roger Nussbaum

We classify all self-dual Einstein four-manifolds invariant under a principal action of the three-dimensional Heisenberg group with non-degenerate orbits. The metrics are explicit and we find, in particular, that the Einstein constant can…

Differential Geometry · Mathematics 2022-11-23 Vicente Cortés , Ángel Murcia

We construct a concrete isomorphism from the permutohedral variety to the regular semisimple Hessenberg variety associated to the Hessenberg function $h_+(i)=i+1$, $1\le i\le n-1$. In the process of defining the isomorphism, we introduce a…

Algebraic Geometry · Mathematics 2022-10-13 Jan-Li Lin

We consider the {\it fractal von Neumann entropy} associated with the {\it fractal distribution function} and we obtain for some {\it universal classes h of fractons} their entropies. We obtain also for each of these classes a {\it…

Statistical Mechanics · Physics 2008-11-26 Wellington da Cruz

We initiate the study of quadratic discrepancy for finite point sets on the Heisenberg group $\mathbb H^n$ with respect to upper Ahlfors regular probability measures. For a natural family of test sets given by left translations and…

Classical Analysis and ODEs · Mathematics 2026-01-23 Luca Brandolini , Alessandro Monguzzi , Matteo Monti

We prove that ideal sub-Riemannian manifolds (i.e., admitting no non-trivial abnormal minimizers) support interpolation inequalities for optimal transport. A key role is played by sub-Riemannian Jacobi fields and distortion coefficients,…

Differential Geometry · Mathematics 2018-11-30 Davide Barilari , Luca Rizzi

One primary objective in submanifold geometry is to discover fascinating and significant classical examples of $H_1$. In this paper which relies on the theory we established in [Adv. Math. 405 (2022), 08514, 50 pages, arXiv:2101.11780] and…

Differential Geometry · Mathematics 2025-02-19 Hung-Lin Chiu , Sin-Hua Lai , Hsiao-Fan Liu

We provide a generalization of continued fractions to the Heisenberg group. We prove an explicit estimate on the rate of convergence of the infinite continued fraction and several surprising analogs of classical formulas about continued…

Number Theory · Mathematics 2016-06-21 Anton Lukyanenko , Joseph Vandehey

We prove a Stepanov differentiability type theorem for intrinsic graphs in sub-Riemannian Heisenberg groups.

Metric Geometry · Mathematics 2025-07-08 Marco Di Marco , Andrea Pinamonti , Davide Vittone , Kilian Zambanini

This paper studies the geometry of bilipschitz maps $f \colon \mathbb{W} \to \mathbb{H}$, where $\mathbb{H}$ is the first Heisenberg group, and $\mathbb{W} \subset \mathbb{H}$ is a vertical subgroup of co-dimension $1$. The images…

Classical Analysis and ODEs · Mathematics 2020-11-17 Tuomas Orponen