\documentclass[12pt]{article} \usepackage[landscape]{geometry} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amsthm} \renewcommand{\phi}{\varphi} \begin{document} \noindent The least fixed point of \begin{align*} h & : (\mathbb{N}_\bot \to \mathbb{Z}_\bot) \to (\mathbb{N}_\bot \to \mathbb{Z}_\bot) \\ h(F)(n) & = \begin{cases} 1 & n = 1 \\ (\phi^{n/2} + (-\phi)^{-n/2})\, F_{n/2} & n \textrm{ is even} \\ \sqrt[3]{\frac{\phi^{3n+1}-\phi F_{3n+1}}{10} + \frac{\sqrt{25 \phi^{3n+1} - 25\phi F_{3n+1} - 20}}{50}} + \sqrt[3]{\frac{\phi^{3n+1}-\phi F_{3n+1}}{10} - \frac{\sqrt{25 \phi^{3n+1} - 25\phi F_{3n+1} - 20}}{50}} & \textrm{otherwise} \\ \end{cases} \end{align*} is the Fibonacci sequence if and only if the Collatz conjecture is true. \end{document}