A Gruss inequality for n-positive linear maps
Abstract: Let $\mathscr{A}$ be a unital $C*$-algebra and let $\Phi: \mathscr{A} \to {\mathbb B}({\mathscr H})$ be a unital $n$-positive linear map between $C*$-algebras for some $n \geq 3$. We show that $$|\Phi(AB)-\Phi(A)\Phi(B)| \leq \Delta(A,||\cdot||)\,\Delta(B,||\cdot||)$$ for all operators $A, B \in \mathscr{A}$, where $\Delta(C,|\cdot|)$ denotes the operator norm distance of $C$ from the scalar operators.
Paper Prompts
Sign up for free to create and run prompts on this paper using GPT-5.
Top Community Prompts
Collections
Sign up for free to add this paper to one or more collections.