Reblogged from What's new:

One of the basic problems in the field of operator algebras is to develop a functional calculus for either a single operator $latex {A}&fg=000000$, or a collection $latex {A_1, A_2, \ldots, A_k}&fg=000000$ of operators. These operators could in principle act on any function space, but typically one either considers complex matrices (which act on a complex finite dimensional space), or operators (either bounded or unbounded) on a complex Hilbert space.

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