Best Approximations in Hardy Spaces on Infinite-Dimensional Unitary Matrix Groups

الملخص EN

We investigate the problem of best approximations in the Hardy space of complex functions, defined on the infinite-dimensional unitary matrix group.

Applying an abstract Besov-type interpolation scale and the Bernstein-Jackson inequalities, a behavior of such approximations is described.

An application to best approximations in symmetric Fock spaces is shown.