## My name is Jie Han (韩杰). I am a postdoc at the Universidade de Sao Paulo (USP) working with Prof. Yoshiharu Kohayakawa since March 2015. I was a visiting research fellow of the University of Birmingham in the academic year 2015 - 2016 and stayed at IMA (Institute for Mathematics and its Applications, Minneapolis, MN) in Fall 2014. I finished my Ph. D. in Georgia State University (GSU) (2010 - 2015) under the supervision of Prof. Yi Zhao. I finished my B. S. in Beijing Institute of Technology (2004 - 2008).## Research: Online papers，ArXivMy research is on graph theory and combinatorics, especially in extremal (hyper)graph theory. Selected papers: - Maximum size of a non-trivial intersecting uniform family that is not a subfamily of the Hilton-Milner family, with Yoshiharu Kohayakawa, Proc. of AMS, 145-1 (2017), 73–87. We determine the maximum size of an intersecting uniform family that is not a subfamily of the EKR family or the HM family, and characterize all extremal families that achieve the maximum size.
- Forbidding Hamilton cycles in uniform hypergraphs, with Yi Zhao, JCTA, 143 (2016) 107-115. We establish a new lower bound for the minimum d-degree thresholds for uniform hypergraphs containing Hamilton l-cycles. In particular, this disproves a conjecture of Rodl and Rucinski.
- Decision problem for Perfect Matchings in Dense k-uniform Hypergraphs, Trans. of AMS, 369-7(2017), 5197-5218. We show that the decision problem for the containment of perfect matchings in k-uniform hypergraphs with minimum codegree at least n/k can be solved in polynomial time. This solves a problem of Karpinski, Rucinski and Szymanska completely and improves the work of Keevash, Knox and Mycroft.
- Minimum codegree threshold for Hamilton l-cycles in k-uniform hypergraphs, with Yi Zhao. JCTA, 132 (2015) 194-223. We determine the minimum codegree threshold for Hamilton l-cycles in k-uniform hypergraphs for all l<k/2. This is best possible and improves the result by Han and Schacht.
- Near perfect matchings k-uniform hypergraphs, CPC, 24 (2015), no. 5, 723-732. We determine the minimum codegree threshold for the so-called near perfect matchings in k-uniform hypergraph, which resolves a conjecture of Rodl, Rucinski and Szemeredi.
## Coauthors: Guantao Chen, Peter Frankl, Wei Gao (2), Hao Huang, Jaehoon Kim, Yoshiharu Kohayakawa (2), Allan Lo (2), Suil O, Nicolás Sanhueza-Matamala, Songling Shan, Andrew Treglown (2), Shoichi Tsuchiya, Chuanyun Zang (2), Yi Zhao (10).Last update: Apr 2017. |