The twisted functions live in L²((-lam, lam)) #
The twisted functions and their even and odd parts are square-integrable on the interval, so they
are genuine elements of the ambient Hilbert space and Submodule.span may be taken of them.
The bound is the only analytic content. ‖fz eta z u‖ = |eta u| · exp(2π u · im z), and on a
bounded interval the exponential is bounded by exp(2π · lam · |im z|), so fz is dominated by a
constant multiple of eta, which is square-integrable by admissibility. Note the twist is not
bounded by 1 unless z is real — that is exactly why the interval has to be bounded.
Also here: the passage from the rescaled zeros as a Set to the Finset that
IsConjInvariant requires.
The twisted function is square-integrable on the interval.
The even part is square-integrable on the interval.
The odd part is square-integrable on the interval.