{ "id": "1501.03267", "version": "v1", "published": "2015-01-14T07:52:53.000Z", "updated": "2015-01-14T07:52:53.000Z", "title": "Operator Lipschitz functions on Banach spaces", "authors": [ "Jan Rozendaal", "Fedor Sukochev", "Anna Tomskova" ], "comment": "30 pages", "categories": [ "math.FA", "math.OA" ], "abstract": "Let $X$, $Y$ be Banach spaces and let $\\mathcal{L}(X,Y)$ be the space of bounded linear operators from $X$ to $Y$. We develop the theory of double operator integrals on $\\mathcal{L}(X,Y)$ and apply this theory to obtain commutator estimates of the form \\begin{align*} \\|f(B)S-Sf(A)\\|_{\\mathcal{L}(X,Y)}\\leq \\textrm{const} \\|BS-SA\\|_{\\mathcal{L}(X,Y)} \\end{align*} for a large class of functions $f$, where $A\\in\\mathcal{L}(X)$, $B\\in \\mathcal{L}(Y)$ are scalar type operators and $S\\in \\mathcal{L}(X,Y)$. In particular, we establish this estimate for $f(t):=|t|$ and for diagonalizable operators on $X=\\ell_{p}$ and $Y=\\ell_{q}$, for $p