Open problems, questions and challenges in finite-dimensional integrable systems

A Bolsinov, VS Matveev, E Miranda… - … Transactions of the …, 2018 - royalsocietypublishing.org
The paper surveys open problems and questions related to different aspects of integrable
systems with finitely many degrees of freedom. Many of the open problems were suggested …

On the integrability of Birkhoff billiards

V Kaloshin, A Sorrentino - Philosophical Transactions of …, 2018 - royalsocietypublishing.org
In this survey, we provide a concise introduction to convex billiards and describe some
recent results, obtained by the authors and collaborators, on the classification of integrable …

On the local Birkhoff conjecture for convex billiards

V Kaloshin, A Sorrentino - Annals of Mathematics, 2018 - projecteuclid.org
The classical Birkhoff conjecture claims that the boundary of a strictly convex integrable
billiard table is necessarily an ellipse (or a circle as a special case). In this article we prove a …

The Birkhoff-Poritsky conjecture for centrally-symmetric billiard tables

M Bialy, AE Mironov - Annals of Mathematics, 2022 - projecteuclid.org
In this paper we prove the Birkhoff-Poritsky conjecture for centrally-symmetric C^2-smooth
convex planar billiards. We assume that the domain A between the invariant curve of 4 …

One can hear the shape of ellipses of small eccentricity

H Hezari, S Zelditch - Annals of Mathematics, 2022 - projecteuclid.org
We show that if the eccentricity of an ellipse is sufficiently small, then up to isometries it is
spectrally unique among all smooth domains. We do not assume any symmetry, convexity …

Compactness of Marked Length Isospectral Sets of Birkhoff Billiard Tables

A Vig - arXiv preprint arXiv:2310.05426, 2023 - arxiv.org
We prove that equivalence classes of marked length isospectral Birkhoff billiard tables are
compact in C^ 2, analogous to the Laplace spectral results of Melrose and Osgood-Phillips …

Birkhoff Conjecture for nearly centrally symmetric domains

V Kaloshin, CE Koudjinan, K Zhang - Geometric and Functional Analysis, 2024 - Springer
In this paper we prove a perturbative version of a remarkable Bialy–Mironov (Ann. Math. 196
(1): 389–413, 2022) result. They prove non perturbative Birkhoff conjecture for centrally …

On some refraction billiards

I De Blasi, S Terracini - arXiv preprint arXiv:2108.11159, 2021 - arxiv.org
The aim of this work is to continue the analysis, started in arXiv: 2105.02108, of the
dynamics of a point-mass particle $ P $ moving in a galaxy with an harmonic biaxial core, in …

Refraction periodic trajectories in central mass galaxies

I De Blasi, S Terracini - Nonlinear Analysis, 2022 - Elsevier
We consider a new type of dynamical systems of physical interest, where two different forces
act in two complementary regions of the space, namely a Keplerian attractive center sits in …

Deformational rigidity of integrable metrics on the torus

J Henheik - Ergodic Theory and Dynamical Systems, 2025 - cambridge.org
It is conjectured that the only integrable metrics on the two-dimensional torus are Liouville
metrics. In this paper, we study a deformative version of this conjecture: we consider …