On a Question of Arveson about Ranks of Hilbert modules
نویسنده
چکیده
It’s well known that the functional Hilbert space H2 over the unit ball Bd ⊂ C , with kernel function K(z, ω) = 1 1−z1ω1−···−zdωd , admits a natural A(Bd)-module structure. We show the rank of a nonzero submodule M ⊂ H2 is infinity if and only if M is of infinite codimension. Together with Arveson’s dilation theory, our result shows that Hilbert modules stand in stark contrast with Hilbert basis theorem for algebraic modules. This result answers a question of Arveson.
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