Ng Hiang Kwui黄炫圭


a.k.a. Xuangui HuangIn P.R. China we are forced to use names in Hanyu Pinyin, a Romanisation system of Mandarin Chinese, as our legal English names, regardless of the actual native languages we speak.

PhD Student
College of Computer and Information Science
Northeastern University

Office: Room 266, West Village HMailling address: Room 202, West Village H, Northeastern University, 360 Huntington Avenue, Boston, MA 02115
Emails: stslxg (at) /
Webs: My goodreads LinkedIn always spams my email. Boycott LinkedIn! The Nearly-dead Chinese facebook Chinese twitter

I'm a first year PhD student in Northeastern University, advised by Prof. Emanuele Viola. Previously I obtained my master's degree in Shanghai Jiao Tong University, advised by Prof. Yijia Chen. I have great enthusiasm for theoretical computer science, especially computational complexity. Previously my research focused on parameterized complexity, circuit complexity, and descriptive complexity. Besides, I had done some research work on correlation decay, recursion theory, and equivalence checking. I love to explore a wide range of research topicsI also have some interest in principles of programming languages, especially type theory., to learn some latest big results/frameworks such as SoS, and to attack challenging open problems.


  • Slicewise Definability in First-Order Logic with Bounded Quantifier Rank
    • with Yijia Chen and Joerg Flum, 26th EACSL Annual Conference on Computer Science Logic (CSL 2017)
    • manuscript, conference version
    • Using color-coding we demonstrate that some parameterized (hyper)graph problems can be slicewise-defined in $\mathrm{FO}_q$ where $q$ is independent of the parameter $k$, and prove the strictness of $\big(\mathrm{XFO}_{q} \big)_{q \in \mathbb{N}}$ by proving that $\mathrm{FO}_{q} \subsetneq \mathrm{FO}_{q+1}$ on arithmetical structures for every $q\in \mathbb{N}$
  • Algorithm for Relatively Small Planted Clique with Small Edge Probability
  • Ladner Theorem in Parameterized Complexity Theory
    • Undergraduate Thesis, supervised by Prof. Yijia Chen, 2014
    • We use finite injury priority method to prove that there are infinitely many $\mathrm{W[1]}$ problems that are neither $\mathrm{W[1]}$-Complete nor $\mathrm{FPT}$ if $\mathrm{FPT} \neq \mathrm{W[1]}$, presenting a "complete" proof which is more accessible to people not well-versed in recursion theory, compared with the original proof by Downey and Fellows

Academic Activities

Reading Seminars Attended and Talks Given

2017 Spring Quantum Computation and Quantum Information
2016 Autumn Quantum Computation and Quantum Information
Sum of Squares Algorithms and Lower Bounds
Spring An Average-Case Depth Hierarchy Theorem for Boolean Circuits
2015 Autumn Holographic Algorithms and Counting Complexity
Spring Communication Complexity
2014 Autumn Advanced Topics on Computational Compleixty
Analysis of Boolean Functions
Summer Finite Injury Method
Spring Kolmogorov Complexity
2013 Autumn Statistical Physics and Algorithms
2012 Autumn Approximation Algorithms
Summer Formal Verification and Automata Theory

Summer Schools and Conferences Participated

2016 Aug. China Theory Week, CUHK
Summer School on Quantum Algorithms and Quantum Programming, GZU
July Coalgebraic Methods for Automata, ECNU
Highlights of Theoretical Computer Science, SHUFE
May Chinese Mathematical Logic Conference, Fudan
2015 Aug. China Theory Week, SJTU
July Logic Summer School in China, ZNU
2014 Aug. BASICS Summer School and Logic Summer School in China, SJTU
June IMS Graduate Summer School in Logic, NUS
May Annual Meeting of Asian Association for Algorithms and Computation, ZJU
2013 Sept. Asian Logic Conference, SYSU
Aug. Summer School on Verification on Infinite State Systems, SJTU
July Asian Initiative for Infinity (AII) Graduate Summer School, NUS

Teaching Assistantships

2016 Summer Theory of Computation, Fudan, for undergraduates
2015 Summer Advanced Algorithms, Fudan, for graduates
Spring Formal Semantics of Programming Languages, SJTU, for graduates
2014 Summer Advanced Algorithms, Fudan, for graduates
2013 Winter Algorithms, SJTU, for undergraduates

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