
The problem of the existence of so-called ``universal functions'' (compare W. Luh, Holomorphic monsters. [J. Approximation Theory 53, No. 2, 128-144 (1988; Zbl 0669.30020)] for the notations and the history of the topic) is generalized. The main result is the following: Let \({\mathcal O} \subset\mathbb{C}\), \({\mathcal O} \neq\mathbb{C}\), be an open set with simply connected components. Then there exists a function \(\varphi\), which is holomorphic exactly on \({\mathcal O}\) and has six universal properties at the same time. The proof uses essentially the theorems of Runge and Mergelyan.
Mathematics(all), Numerical Analysis, Applied Mathematics, Approximation in the complex plane, Analysis
Mathematics(all), Numerical Analysis, Applied Mathematics, Approximation in the complex plane, Analysis
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