Yitong He

Yitong He (Anna),
School of Mathematics and Statistics,
Xi'an Jiaotong University,
Xianning West Road,
Shaanxi,
China,
710049

Tel: +86 15291458352,

Email: yitongh25@gmail.com, yitong.he@stu.xjtu.edu.cn

About me

Hi! I am a senior student majoring in mathematics at Xi'an Jiaotong University. I enjoy the process of solving problems in graph theory and combinatorics, and I have been keeping learning new things and seeking research opportunities to get myself prepared to be a real mathematician. My CV can be found here. Besides math, I love playing tennis, singing, and learning new languages. I am a fluent Chinese and English speaker, and I am recently learning French and Japanese on Duolingo (my parents are also learning English on it :)). I can't resist cute animals like cats and dogs, and now our family has four such lovely members, one Labrador called Laphy, three adopted cats, little Orange, Dudu, and Beans.

Education

Sep.2022 - July.2026 (expected)

Xi'an, China

I am a member of the mathematics experimental class, my current GPA is 4.0/4.3 (92.67/100). I am expected to complete my undergraduate studies and receive a B.Sc. in Science (Honors Program) in July 2026.

Jan.2025 - June.2025

Berkeley, CA

I studied at UC Berkeley in Spring 2025 via the Berkeley Global Access Visiting Student Program. Out of my interest in combinatorics, I enrolled in MATH272, a graduate course instructed by professor Daniel Král, topics include permutons, Szemeredi’s regularity lemma, homomorphism density and graphons, the entropy method in proving the Sidorenko property, and Benjamini-Schramm convergence of sparse graphs are covered.

Sep.2020 - July.2022

Xi'an, China

I joined the Honors Youth Program of Xi'an Jiaotong University in 2020, right after my graduation from my junior high school. In this program, I met young students from all over the country. We participated in mathematical modeling competitions, wrote poems, rehearsed plays, participated in sports games, and forged deep friendships in the process.

Research interests

My research interests include combinatorics and graph theory. To be specific, I am interested in the following topics.

Ramsey theory
Turán type problems
Graph coloring problems
Algebraic combinatorics

As an undergraduate, I am also learning and exploring new topics. Due to my research training experience, I am also interested in the interdisciplinary topics in combinatorics and optimization. One may refer to this page for more information on this field. Interestingly, some graph coloring problems, like the classical four-color problem, can also be viewed as combinatorial optimization problems.

Research experiences and publications

Clocks are e-positive, Discrete Mathematics 349, (2026), https://doi.org/10.1016/j.disc.2025.114723.
The work in this paper was mainly completed in PACE 2024, an REU project focusing on algebraic combinatorics, held by the Beijing International Center for Mathematical Research and Peking University. This is joint work with Luan Chen, and our mentor is David Guoliang Wang. Here is a photo of our group (from left to right: Luan Chen, me, David Guoliang Wang). In this project, our group focused on the positivity of chromatic symmetric functions and showed the $e$-positivity of a special class of theta graphs using the idea of the composition method introduced by our mentor in the paper A composition method for neat formulas of chromatic symmetric functions.

Model-Driven Subspaces for Large-Scale Optimization with Local Approximation Strategy, https://arxiv.org/abs/2509.08256.
This work was mainly completed during my exchange study at UC Berkeley in Spring 2025. I would like to thank Dr Pengcheng Xie, who kindly offered me the opportunity to collaborate and provided me with precious advice as well as ideas during our collaboration. In this work, we designed a novel class of subspaces suitable for classical subspace-based optimization frameworks. Here is a poster about this work. The paper has been submitted to the Mathematics of Operations Research and is currently under review.

I am recently considering a problem of determining the anti-Ramsey number of $K_4^{(3)-}$ in complete 3-graphs. A conjecture about this number is given by my mentor at Xi'an Jiaotong University, Prof. Hongliang Lu. Some of our current ideas can be seen in this slides. I am glad to discuss related problems with people who are also interested in this topic.