Positive isometric Fourier multipliers on non-commutative LpL^p-spaces

This paper characterizes positive surjective isometric Fourier multipliers on non-commutative LpL^p-spaces of a locally compact group for p2p \neq 2, proving that such operators arise if and only if their symbols are locally almost everywhere equal to continuous characters of the group, thereby extending previous results from the unimodular to the general setting.

Christoph Kriegler, Christian Le Merdy, Safoura ZadehTue, 10 Ma🔢 math