Hello and welcome to my home page! Here I post my research background and other related experiences. My name is William Chang and in 2022 I graduated from University of Southern California with a B.A. in mathematics. Since 2023 Fall, I’ve been a PhD student at University of California, Los Angeles in Applied mathematics.

My research interests are rather diverse. It mainly span across mathematics and machine learning. Please see my papers below for more details on my work.

On the side I enjoy tutoring students. I’m willing to tutor students in math and physics at all levels (elementary, middle, high school, and university level as well). You can see my past students and book a session with me via my [Takelessons Profile].

In my free time I like to practice Taekwondo and sing. Please feel free to check out my cover channel on youtube [@WilliamChangMusic]!

Please feel free to reach out to me for anything via chang314@g.ucla.edu!

1. Curvature on Graphs
   Fariba Ariaei, William Chang
   Under Preparation

2. LinUCB in Multiplayer Information Asymmetric Contextual Bandits
   William Chang, Terry Lu
   Under Review at Association for the Advancement of Artificial Intelligence, 2024

3. Optimal Cooperative Multiplayer Learning Bandits with Noisy Rewards and No Communication
   William Chang, Terry Lu
   Under Review at Association for the Advancement of Artificial Intelligence, 2024

4. Mixing on Generalized Associahedra
   William Chang, Colin Defant, Daniel Frishberg
   Under Review at International Symposium on Algorithms and Computation, 2023

5. No-Regret Online Reinforcement Learning with Adversarial Losses and Transitions [PDF]
   Tiancheng Jin, Junyan Liu, Chloé Rouyer, William Chang, Chen-Yu Wei, Haipeng Luo
   Under Review at Neural Information Processing Systems, 2023

6. Finite-Time Regret Bound of Multi-Agent Thompson Sampling
   Tianyuan Jin, Haolun Hsu, William Chang, Pan Xu
   Under Review at Neural Information Processing Systems, 2023

7. Understanding Domain Adaptation in the Lens of Causality [PDF]
   William Chang, Haohan Wang
   Under Review at Neural Information Processing Systems, 2023

8. Mixup to the Random Extreme and Its Performances in Robust Image Classification [PDF]
   Jackie Chen, Qianjing Chen, William Chang, Haohan Wang
   Transactions on Machine Learning Research, 2023

9. Bode Integral Limitation For Irrational Systems [PDF]
   William Chang, Fariba Ariaei, Edmond Jonckheere
   International Federation of Automatic Control, 2023

10. Approximation Capabilities of Neural Networks using Morphological Perceptions and Generalizations [PDF]
    William Chang, Hassan Hamad, Keith Chugg
    Asilomar conference on signals, systems, and computers, 2022

11. Online Learning for Cooperative Multi-Player Multi-Armed Bandits [PDF]
    William Chang, Mehdi Jafarnia-Jahromi, Rahul Jain
    IEEE Conference on Decision and Control, 2022

1. Nearly Tight Expansion Bounds on Generalized Associahedra
   William Chang, Colin Defant, Daniel Frishberg
   Under Preparation

2. Closure of Certain Matrix Varieties and Applications [PDF]
   William Chang, Robert Guralnick
   European Journal of Mathematics

3. Finite-time singularities in a generalized elastohydrodynamic lubrication equation [PDF]
   William Chang, Hangjie Ji
   Under Review at Applied Mathematics Letters, 2023

4. Stochastic Couplings and Bijections from the Symmetric Group to itself [PDF]
   William Chang
   Mathematical Journal of Okayama University, 2023

5. Compatibility in Ozsvath-Szabo’s bordered HFK via higher representations [PDF]
   William Chang, Andrew Manion
   The Pacific Journal of Mathematics, 2023

2023 CDC Conference Referee [Website]

2023 IFAC Conference Referee [Website]

2022 Asilomar conference on signals, systems, and computers [Website]
Approximation Capabilities of Neural Networks using Morphological Perceptions and Generalizations

2022 IEEE Conference on Decision and Control [Website]
Online learning for Cooperative Multi-Player Multi-Armed Bandits

2022 AMS-PME Joint Mathematics Meeting Undergraduate Poster Session [Website]
Asymptotical bounds on maximal cliques in $K_t$-minor free graphs