On the convexity of the KdV Hamiltonian

Autor: Kappeler, Thomas, Maspero, Alberto, Molnar, Jan-Cornelius, Topalov, Peter
Rok vydání: 2015
Předmět:
Zdroj: Communications in Mathematical Physics, 346(1): 191-236, 2016
Druh dokumentu: Working Paper
DOI: 10.1007/s00220-015-2563-x
Popis: We prove that the nonlinear part $H^{*}$ of the KdV Hamiltonian $H^{kdv}$, when expressed in action variables $I = (I_{n})_{n\ge 1}$, extends to a real analytic function on the positive quadrant $\ell^2_+(\mathbb N)$ of $\ell^{2}(\mathbb N)$ and is strictly concave near $0$. As a consequence, the differential of $H^{*}$ defines a local diffeomorphism near $0$ of $\ell_{\mathbb C}^{2}(\mathbb N)$.
Comment: 48 pages
Databáze: arXiv