# Evaluate Winding Numbers through Cauchy Indices

 Title: Evaluate Winding Numbers through Cauchy Indices Author: Wenda Li Submission date: 2017-10-17 Abstract: In complex analysis, the winding number measures the number of times a path (counterclockwise) winds around a point, while the Cauchy index can approximate how the path winds. This entry provides a formalisation of the Cauchy index, which is then shown to be related to the winding number. In addition, this entry also offers a tactic that enables users to evaluate the winding number by calculating Cauchy indices. BibTeX: @article{Winding_Number_Eval-AFP, author = {Wenda Li}, title = {Evaluate Winding Numbers through Cauchy Indices}, journal = {Archive of Formal Proofs}, month = oct, year = 2017, note = {\url{http://isa-afp.org/entries/Winding_Number_Eval.html}, Formal proof development}, ISSN = {2150-914x}, } License: BSD License Depends on: Budan_Fourier, Sturm_Tarski Used by: Count_Complex_Roots, Zeta_Function