Abstract

The Fundamental Theorem of Algebra is a useful tool in determining the number of zeros of complex-valued polynomials and rational functions. It does not, however, apply to complex-valued harmonic polynomials and rational functions generally. In this thesis, we determine behaviors of the family of complex-valued harmonic functions $f_{c}(z) = z^{n} + \frac{c}{\overline{z}^{k}} - 1$ that defy intuition for analytic polynomials. We first determine the sum of the orders of zeros by using the harmonic analogue of Rouch\'e's Theorem. We then determine useful geometry of the critical curve and its image in order to count winding numbers by applying the harmonic analogue of the Argument Principle. Combining these results, we fully determine the number of zeros of $f_{c}$ for $c > 0$.

Degree

MS

College and Department

Physical and Mathematical Sciences; Mathematics

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2022-12-12

Document Type

Thesis

Handle

http://hdl.lib.byu.edu/1877/etd12650

Keywords

complex analysis, complex-valued harmonic function, epicycloid

Language

english

Share

COinS