International Joint Conference On Theoretical Computer Science – Frontier of Algorithmic Wisdom

August 15-19, 2022, City University of Hong Kong, Hong Kong


Invited Speakers

Young Faculty Forum in TCS

Survivable Network Design: Group-Connectivity

Yuhao Zhang

Shanghai Jiao Tong University

In the classical survivable network design problem (SNDP), we are given an undirected graph $G=(V,E)$ with costs on edges and a connectivity requirement $k(s,t)$ for each pair of vertices. The goal is to find a minimum-cost subgraph $H\subseteq V$ such that every pair $(s,t)$ are connected by $k(s,t)$ edge or (openly) vertex disjoint paths, abbreviated as EC-SNDP and VC-SNDP, respectively. The seminal result of Jain [FOCS'98, Combinatorica'01] gives a $2$-approximation algorithm for EC-SNDP, and a decade later, an $O(k^3\log n)$-approximation algorithm for VC-SNDP, where $k$ is the largest connectivity requirement, was discovered by Chuzhoy and Khanna [FOCS'09, Theory Comput.'12]. While there is a rich literature on point-to-point settings of SNDP, the viable case of connectivity between subsets is still relatively poorly understood.
This paper concerns the generalization of SNDP into the subset-to-subset setting, namely Group EC-SNDP. We develop the framework, which yields the first non-trivial (true) approximation algorithm for Group EC-SNDP. Previously, only a bicriteria approximation algorithm is known for Group EC-SNDP [Chalermsook, Grandoni, and Laekhanukit, SODA'15], and a true approximation algorithm is known only for the single-source variant with connectivity requirement $k(S,T)\in\{0,1,2\}$ [Gupta, Krishnaswamy, and Ravi, SODA'10; Khandekar, Kortsarz, and Nutov, FSTTCS'09 and Theor. Comput. Sci.'12].

I am an Assistant Professor of John Hopcroft Center for Computer Science at Shanghai Jiao Tong University since 2021, working in the field of theoretical computer science. I obtained my Ph.D. (2016~2020) from the Department of Computer Science at the University of Hong Kong, Supervised by Dr. Zhiyi Huang. Before that, I got my B.E from the College of Computer Science and Technology at Zhejiang University (2012~2016). During my undergraduate study, I started to be interested in theoretical computer science when I joined the research group of Prof. Guochuan Zhang. I'm interested in Online Algorithms and Approximation Algorithms. My research aims to design algorithms for real-world applications with a provable guarantee and to develop general mathematical tools in their performance analysis.