Preservers of the $p$-power and the Wasserstein means on $2\times 2$ matrices

Richárd Simon, Dániel Virosztek

In one of his recent papers \cite{ML1}, Molnár showed that if $\mathcal{A}$ is a von Neumann algebra without $I_1,I_2$-type direct summands, then any function from the positive de…