An Investigation in to the Properties of Functions Defining Distinguished Varieties
U. D. Wijesooriya *
Department of Mathematics, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka.
Y. G. D. M. Dharmasiri
Department of Mathematics, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka.
R. D. P. M. Wijerathne
Department of Mathematics, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka.
*Author to whom correspondence should be addressed.
Abstract
An inner toral polynomial is a polynomial in \(\mathbb{C}\) [z,w] such that its zero set is contained in \(\mathbb{D}\)2 \(\cup\) \(\mathbb{T}\)2 \(\cup\) \(\mathbb{E}\)2 where \(\mathbb{D}\) is the open unit disc, \(\mathbb{T}\) is the unit circle and \(\mathbb{E}\) is the exterior of the closed unit disc in \(\mathbb{C}\). Given such a polynomial p, it's zero set that lies inside \(\mathbb{D}\)2 , i.e V = Z (p) \(\cap\) \(\mathbb{D}\)2 is called a distinguished variety, and p is called a polynomial defining the distinguished variety V . An inner toral polynomial always gives a distinguished variety and vice versa. Finite Blaschke products generate inner toral polynomials such a way that, given a finite Blaschke product B(z) the numerator of wm - B(z) is an inner toral polynomial. In this paper, we investigate the conditions that make the sum and the composition of inner toral polynomials generated by finite Blaschke products, inner toral.
Keywords: Automorphisms, blaschke products, distinguished varieties, inner toral polynomials