MathDB
complex subset is not dependent

Source: Miklos Schweitzer 2020, Problem 9

December 1, 2020
topologycomplex analysiscomplex numberscollege contestsMiklos Schweitzer

Problem Statement

Let DCD\subseteq \mathbb{C} be a compact set with at least two elements and consider the space \Omega=\bigtimes_{i=1}^{\infty} D with the product topology. For any sequence (dn)n=0Ω(d_n)_{n=0}^{\infty} \in \Omega let f(dn)(z)=n=0dnznf_{(d_n)}(z)=\sum_{n=0}^{\infty}d_nz^n, and for each point ζC\zeta \in \mathbb{C} with ζ=1|\zeta|=1 we define S=S(ζ,(dn))S=S(\zeta,(d_n)) to be the set of complex numbers ww for which there exists a sequence (zk)(z_k) such that zk<1|z_k|<1, zkζz_k \to \zeta, and fdn(zk)wf_{d_n}(z_k) \to w. Prove that on a residual set of Ω\Omega, the set SS does not depend on the choice of ζ\zeta.