{ "id": "1605.03472", "version": "v1", "published": "2016-05-11T15:17:40.000Z", "updated": "2016-05-11T15:17:40.000Z", "title": "A sufficient condition for a Rational Differential Operator to generate an Integrable System", "authors": [ "Sylvain Carpentier" ], "categories": [ "math-ph", "math.MP", "math.RA" ], "abstract": "For a rational differential operator $L=AB^{-1}$, the Lenard-Magri scheme of integrability is a sequence of functions $F_n, n\\geq 0$, such that (1) $B(F_{n+1})=A(F_n)$ for all $n \\geq 0$ and (2) the functions $B(F_n)$ pairwise commute. We show that, assuming that property $(1)$ holds and that the set of differential orders of $B(F_n)$ is unbounded, property $(2)$ holds if and only if $L$ belongs to a class of rational operators that we call integrable. If we assume moreover that the rational operator $L$ is weakly non-local and preserves a certain splitting of the algebra of functions into even and odd parts, we show that one can always find such a sequence $(F_n)$ starting from any function in Ker B. This result gives some insight in the mechanism of recursion operators, which encode the hierarchies of the corresponding integrable equations.", "revisions": [ { "version": "v1", "updated": "2016-05-11T15:17:40.000Z" } ], "analyses": { "keywords": [ "rational differential operator", "sufficient condition", "integrable system", "rational operator", "differential orders" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }