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It is shown that a Banach space with locally uniformly convex dual admits an equivalent norm which is itself locally uniformly convex. It follows that on any such space all continuous real-valued functions may be uniformly approximated by…

Functional Analysis · Mathematics 2007-05-23 Richard Haydon

Given a pseudoconvex hypersurface in C^n and an arbitrary weight, we show the existence of local coordinates in which the polynomial model contains a particularly simple sum of squares of monomials. Our second main result provides a…

Complex Variables · Mathematics 2018-06-06 Alexander Basyrov , Andreea C. Nicoara , Dmitri Zaitsev

Let $K$ be a compact subset of a totally-real manifold $M$, where $M$ is either a $\mathcal{C}^2$-smooth graph in $\mathbb{C}^{2n}$ over $\mathbb{C}^n$, or $M=u^{-1}\{0\}$ for a $\mathcal{C}^2$-smooth submersion $u$ from $\mathbb{C}^n$ to…

Complex Variables · Mathematics 2015-04-28 Sushil Gorai

The singularity structure of solutions of a class of Hamiltonian systems of ordinary differential equations in two dependent variables is studied. It is shown that for any solution, all movable singularities, obtained by analytic…

Classical Analysis and ODEs · Mathematics 2013-12-17 Thomas Kecker

We show that local deformations, near closed subsets, of solutions to open partial differential relations can be extended to global deformations, provided all but the highest derivatives stay constant along the subset. The applicability of…

Differential Geometry · Mathematics 2021-09-01 Christian Baer , Bernhard Hanke

We describe the topology of a general polynomial mapping $f:\Bbb C^2\to\Bbb C^2.$

Algebraic Geometry · Mathematics 2016-02-09 M. Farnik , Z. Jelonek , M. A. S. Ruas

We prove that uniform hyperbolicity is invariant under topological conjugacy for dissipative polynomial automorphisms of C^2. Along the way we also show that a sufficient condition for hyperbolicity is that local stable and unstable…

Complex Variables · Mathematics 2020-06-04 Eric Bedford , Romain Dujardin

This work is devoted to a systematic study of symplectic convexity for integrable Hamiltonian systems with elliptic and focus-focus singularities. A distinctive feature of these systems is that their base spaces are still smooth manifolds…

Symplectic Geometry · Mathematics 2018-09-18 Tudor Ratiu , Christophe Wacheux , Nguyen Tien Zung

We show that for bounded domains in $\mathbb C^n$ with $\mathcal C^{1,1}$ smooth boundary, if there is a closed set $F$ of $2n-1$-Lebesgue measure $0$ such that $\partial \Omega \setminus F$ is $\mathcal C^{2}$-smooth and locally…

Complex Variables · Mathematics 2025-10-22 Quang Dieu Nguyen , Pascal J. Thomas

In this article we prove a global result in the spirit of Basener's theorem regarding the relation between q-pseudoconvexity and q-holomorphic convexity: we prove that any smoothly bounded strictly q-pseudoconvex open subset of the complex…

Complex Variables · Mathematics 2018-09-05 George-Ionut Ionita , Ovidiu Preda

In this paper we extend the dichotomy given by Samuelsson and Wold that can be thought of as an analogue of the Wermer maximality theorem in $\mathbb{C}^2$ for certain polynomial polyhedra. We consider complex non-degenerate simply…

Complex Variables · Mathematics 2025-03-04 Sushil Gorai , Golam Mostafa Mondal

Let $S$ be a smooth, totally real, compact immersion in $\mathbb{C}^n$ of real dimension $m \leq n$, which is locally polynomially convex and it has finitely many points where it self-intersects finitely many times, transversely or…

Complex Variables · Mathematics 2023-08-01 Octavian Mitrea

In this work we prove that every locally symmetric smooth submanifold gives rise to a naturally defined smooth submanifold of the space of symmetric matrices, called spectral manifold, consisting of all matrices whose ordered vector of…

Optimization and Control · Mathematics 2012-12-18 Aris Daniilidis , Jerome Malick , Hristo Sendov

We describe the topology of a general polynomial mapping $F=(f, g):X\to\Bbb C^2$, where $X$ is a complex plane or a complex sphere.

Algebraic Geometry · Mathematics 2018-09-24 M. Farnik , Z. Jelonek , M. A. S. Ruas

We show that locally homogeneous $\mathcal{C}^0$-Riemannian manifolds are smooth.

Metric Geometry · Mathematics 2022-04-28 Nina Lebedeva , Artem Nepechiy

While intersections of convex sets are convex, their unions have rather complicated behavior. Some natural contexts where they appear include duality arguments involving boundaries of convex sets and valuations, which have an Euler…

Combinatorics · Mathematics 2026-02-06 Soohyun Park

In this work one proves that, around each point of a dense open set (regular points), a real analytic or holomorphic bihamiltonian structure decomposes into a product of a Kronecker bihamiltonian structure and a symplectic one if a…

Symplectic Geometry · Mathematics 2011-07-13 Francisco-Javier Turiel

Strongly convex sets in Hilbert spaces are characterized by local properties. One quantity which is used for this purpose is a generalization of the modulus of convexity \delta_\Omega of a set \Omega. We also show that \lim_{\epsilon \to 0}…

Metric Geometry · Mathematics 2013-04-08 Alexander Weber , Gunther Reißig

Given a closed subset $\La$ of the open unit ball $B_1\subset \real^n$, $n \geq 3$, we will consider a complete Riemannian metric $g$ on $\bar{B_1} \setminus \La$ of constant scalar curvature equal to $n(n-1)$ and conformally related to the…

Differential Geometry · Mathematics 2007-11-09 Marcos P. Cavalcante

We show that the boundary of any bounded strongly pseudoconvex complete circular domain in $\mathbb C^2$ must contain points that are exceptionally tangent to a projective image of the unit sphere.

Complex Variables · Mathematics 2020-03-06 David E. Barrett , Dusty E. Grundmeier