Toeplitz Operators on Abstract Hardy Spaces Built upon Banach Function Spaces

الملخص EN

Let X be a Banach function space over the unit circle T and let H[X] be the abstract Hardy space built upon X.

If the Riesz projection P is bounded on X and a∈L∞, then the Toeplitz operator Taf=P(af) is bounded on H[X].

We extend well-known results by Brown and Halmos for X=L2 and show that, under certain assumptions on the space X, the Toeplitz operator Ta is bounded (resp., compact) if and only if a∈L∞ (resp., a=0).

Moreover, aL∞≤TaB(H[X])≤PB(X)aL∞.

These results are specified to the cases of abstract Hardy spaces built upon Lebesgue spaces with Muckenhoupt weights and Nakano spaces with radial oscillating weights.