Modified Bers operators and the duality of multiplicative holomorphic automorphic forms

The integral Bers operator, related to a reflection in some quasicircle, plays an important role in the theory of single-valued automorphic forms [1, 2]. Study was started in [3] of the normed spaces of measurable and multiplicative holomorphic automorphic forms for a Fuchsian group. In the present article we introduce some basic multiplicative modifications of the Bers operator and the corresponding bilinear pairing in connection with duality in the spaces of multiplicative holomorphic automorphic forms. Under study we obtain a universal norm estimate and establish selfadjointness for all operators.