Abstract

this paper is to give a simple, self-contained approach to this problem, giving back the subdifferential formula for (1.2) in [13] for example. Our idea will be to generalize von Neumann's result somewhat by asking which convex functions (rather than simply norms) are unitarily invariant: appropriately, the key idea will be a Fenchel conjugacy formula analogous to von Neumann's polarity formula (1.1): (f ffi oe)

Citations

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