We describe the structure of those transformations on certain sets of positive operators which preserve the p-norm of linear combinations with given nonzero real coefficients. These sets are the collection of all positive pth Schatten-class operators and the set of its normalized elements. The results of the work generalize, extend, and unify several former theorems.
Gergő Nagy. "Preservers for the -Norm of Linear Combinations of Positive Operators." Abstr. Appl. Anal. 2014 1 - 9, 2014. https://doi.org/10.1155/2014/434121