From: Tobias Nipkow <nipkow@in.tum.de>
The Poincaré-Bendixson Theorem
Fabian Immler and Yong Kiam Tan
The Poincaré-Bendixson theorem is a classical result in the study of 
(continuous) dynamical systems. Colloquially, it restricts the possible 
behaviors of planar dynamical systems: such systems cannot be chaotic. In 
practice, it is a useful tool for proving the existence of (limiting) periodic 
behavior in planar systems. The theorem is an interesting and challenging 
benchmark for formalized mathematics because proofs in the literature rely on 
geometric sketches and only hint at symmetric cases. It also requires a 
substantial background of mathematical theories, e.g., the Jordan curve theorem, 
real analysis, ordinary differential equations, and limiting (long-term) 
behavior of dynamical systems.
https://www.isa-afp.org/entries/Poincare_Bendixson.html
Enjoy!
smime.p7s
Last updated: Nov 04 2025 at 01:44 UTC