The Semi-Classical Sine-Gordon Equation, Universality at the Gradient Catastrophe and the Painlevé-I Equation by Bingying Lu A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Mathematics) in the University of Michigan 2018 Doctoral Committee: Professor Peter Miller, Chair Professor Jinho Baik Professor Charles Doering Professor Herbert Winful Professor Sijue Wu Bingying Lu
[email protected] ORCID iD: 0000-0001-6918-7211 c Bingying Lu 2018 Dedication To Lemur1, Lexie, Leeway and Lu Wu 1https://en.wikipedia.org/wiki/Lemur. A clade of strepsirrhine primates endemic to the island of Mada- gascar. ii Acknowledgements I want to thank everyone who made this thesis possible, in particular, my cheerful best friends, especially Wei Li, for their moral support; my gloomy best friends for listening to my existential anguish (many of them overlap); my parents for their unquestioning support of my daydreams; people I met in graduate school who taught me maths and otherwise; Mathematica for usually reliably converging to one answer after four to ten tries; Christian Klein who generously provided a Matlab code to help us visualise the solutions and pointed out that I can dive into cab driving business if mathematics ever not work out for me; Liming Ling for teaching me to find and plot rogue wave solutions; Guilherme Silva for teaching me how to generate videos in TEX; Samantha Xu who gave me a beamer template with a lemur—I left beamer but the lemur stayed; Songdi Fan for proofreading and attempting to add 500 determiners to my thesis (and th-fronting the word thesis); Wei Li (again!) for helping me with formatting; the very patient committee members for their guidance; and my advisor Peter Miller: I was convinced from the very beginning that he had worked out my thesis in the back of his mind but just wouldn’t tell me the answer.