}} - *Truly Low-Space Element Distinctness and Subset Sum via Pseudorandom Hash Functions* [https://arxiv.org/abs/2111.01759 \[arxiv\]] {{ [abstract]

}} - *Hardness vs Randomness, Revised: Uniform, Non-Black-Box, and Instance-Wise* [https://eccc.weizmann.ac.il/report/2021/080/ \[eccc\]] [nonbb-derand-final.pptx \[slides by me\] ] [https://sites.google.com/site/roeitell/Publications?authuser=0 \[slides by Roei\] ] {{ [short summary]

}} == *Selected Publications* === *Derandomization* - *When Arthur has Neither Random Coins nor Time to Spare: Superfast Derandomization of Proof Systems* [https://eccc.weizmann.ac.il/report/2022/057/ \[eccc\]] - *Unstructured Hardness to Average-Case Randomness* [https://eccc.weizmann.ac.il/report/2022/097/ \[eccc\]]\n Lijie Chen, Ron D. Rothblum, Roei Tell. /Foundations of Computer Science/ (FOCS 2022)\n - *Hardness vs Randomness, Revised: Uniform, Non-Black-Box, and Instance-Wise* [https://eccc.weizmann.ac.il/report/2021/080/ \[eccc\]] [nonbb-derand-final.pptx \[slides\] ] [https://www.youtube.com/watch?v=v4xMEKAS07A \[Roei's talk at TCS plus\]] [https://drive.google.com/file/d/1L2z3USxzrIVpJbfFI1EyuZtyQ2BmYJSF/view \[Roei's slides\]] {{ [short summary]

}} Lijie Chen, [https://sites.google.com/site/roeitell/ Roei Tell]. /Foundations of Computer Science/ (FOCS 2021). {{}}Invited to the SICOMP Special Issue for FOCS 2021{{}}\n - *Simple and fast derandomization from very hard functions: Eliminating randomness at almost no cost* [https://eccc.weizmann.ac.il/report/2020/148/ \[eccc\]] [http://www.wisdom.weizmann.ac.il/~oded/MC/294.html \[Oded's choice\]] [optimalderand-2020-ICT-CAS.pptx \[slides by me\]] [roei-slides-fast-derand.pdf \[slides by Roei\]] {{ [short highlight]

[longer summary]

}} Lijie Chen, [https://sites.google.com/site/roeitell/ Roei Tell]. /Symposium on the Theory of Computing/ (STOC 2021)\n === *Circuit Lower Bounds from Algorithms* - *Almost Everywhere Circuit Lower Bounds from Non-Trivial Derandomization* [https://eccc.weizmann.ac.il/report/2020/150/ \[eccc\]] [https://www.youtube.com/watch?v=vpyoZdv--nw&list=PL3DbynX8gwfJLYrm4EoZn6aK7IAACiTKa&index=6 \[video by Xin Lyu in FOCS 2020\]] [Ryan-slides-ae-lowerbound.pdf \[slides by Ryan\]] {{ [short highlight]

}} Lijie Chen, Xin Lyu, [https://people.csail.mit.edu/rrw/ Ryan Williams]. /Foundations of Computer Science/ (FOCS 2020)\n - *Strong Average-Case Circuit Lower Bounds from Non-trivial Derandomization* [https://eccc.weizmann.ac.il/report/2020/010/ \[eccc\]] [Reunion_Talk.pptx \[slides at Simons (for complexity theorist)\]] [IAS_Talk.pptx \[slides at IAS (intense version)\]] [Warwick_Talk.pptx \[slides at Warwick (lightweight version)\]] {{ [short highlight]

}} Lijie Chen, [https://hanlin-ren.github.io/ Hanlin Ren]. /Symposium on the Theory of Computing/ (STOC 2020). {{}}Invited to the SICOMP Special Issue for STOC 2020{{}}\n - *Non-deterministic Quasi-Polynomial Time is Average-case Hard for ACC Circuits* [Austin-NQP-Average-Case-Lower-Bound.pptx \[Talk at UT Austin's Theory Seminar\]] [https://eccc.weizmann.ac.il/report/2019/031/ \[eccc\]] [Che19-journal-version.pdf \[draft of journal version\]]\n Lijie Chen. /Foundations of Computer Science/ (FOCS 2019). {{}}Invited to the SICOMP Special Issue for FOCS 2019{{}}\n - *Efficient Construction of Rigid Matrices Using an NP Oracle* [FOCS_2019_rigidmatrix.pdf \[pdf\]] [FOCS_2019_rigidmatrix_slides.pptx \[slides\]] [http://www.wisdom.weizmann.ac.il/~oded/MC/281.html \[Oded's choice\]] {{ [short highlight]

}} [http://joshalman.com/ Josh Alman], Lijie Chen. /Foundations of Computer Science/ (FOCS 2019). {{}}Machtey Award for Best Student Paper. Invited to the SICOMP Special Issue for FOCS 2019{{}}\n === *Hardness Magnification* (Strong Lower Bounds from Much Weaker Lower Bounds) - *Beyond Natural Proofs: Hardness Magnification and Locality* [https://eccc.weizmann.ac.il/report/2019/168/ \[eccc\]] [https://arxiv.org/abs/1911.08297 \[arxiv\]] [https://www.dcs.warwick.ac.uk/~igorcarb/documents/papers/magnification-note.pdf \[notes by Igor\]] {{ [short highlight]

}} Lijie Chen, [https://researchmap.jp/shuichi.hirahara/ Shuichi Hirahara],[https://www.dcs.warwick.ac.uk/~igorcarb/ Igor Oliveira], [http://users.ox.ac.uk/~coml0742/ Jan Pich], [https://www.cs.ox.ac.uk/people/ninad.rajgopal/ Ninad Rajgopal], [https://www.cs.ox.ac.uk/people/rahul.santhanam/ Rahul Santhanam]. /Innovations in Theoretical Computer Science/ (ITCS 2020)\n - *Hardness Magnification for all Sparse NP Languages* [https://eccc.weizmann.ac.il/report/2019/118/ \[eccc\]] \n Lijie Chen, [https://ce-jin.github.io/ Ce Jin], [https://people.csail.mit.edu/rrw/ Ryan Williams]. /Foundations of Computer Science/ (FOCS 2019)\n - *Bootstrapping Results for Threshold Circuits "Just Beyond" Known Lower Bounds* [https://eccc.weizmann.ac.il/report/2018/199/ \[eccc\]] [http://www.wisdom.weizmann.ac.il/~oded/MC/256.html \[Oded's choice\]] {{ [short highlight]

}} Lijie Chen, [https://sites.google.com/site/roeitell/ Roei Tell]. /Symposium on the Theory of Computing/ (STOC 2019). {{}}Danny Lewin Best Student Paper Award{{}}\n === *Other Topics* - (Quantum Supremacy) *Complexity-Theoretic Foundations of Quantum Supremacy Experiments* [http://eccc.hpi-web.de/report/2016/200/ \[eccc\]] [https://arxiv.org/abs/1612.05903 \[arxiv\]] [CCC_2017_QuantumSupremacy.pdf \[slides\]]\n [https://www.scottaaronson.com/ Scott Aaronson], Lijie Chen. /Computational Complexity Conference/ (CCC 2017). {{}}Invited to the Toc Special Issue for CCC 2017{{}}\n - (Streaming Lower Bounds) *Almost Optimal Super-Constant-Pass Streaming Lower Bounds for Reachability* [https://eccc.weizmann.ac.il/report/2021/027/ \[eccc]]\n Lijie Chen, Gillat Kol, Dmitry Paramonov, Raghuvansh Saxena, Zhao Song, [https://www.cs.princeton.edu/~hy2/ Huacheng Yu]. /Symposium on the Theory of Computing/ (STOC 2021). {{}}Invited to the SICOMP Special Issue for STOC 2021{{}}\n - (Fine-grained Complexity) *On The Hardness of Approximate and Exact (Bichromatic) Maximum Inner Product* [https://eccc.weizmann.ac.il/report/2018/026/ \[eccc\] ] [https://arxiv.org/abs/1802.02325 \[arxiv\]] [CCC_2018_MaxIP.pptx \[slides\] ] [https://theoryofcomputing.org/articles/v016a004/ \[journal version\]] {{ [short highlight]

}} Lijie Chen. /Computational Complexity Conference/ (CCC 2018). {{}} Invited to the Toc Special Issue for CCC 2018{{}}\n - (Differential Privacy) *On Distributed Differential Privacy and Counting Distinct Elements* [https://arxiv.org/abs/2009.09604 \[arxiv]] [countDistinct-long.pptx \[long slides\]] [countDistinct-short.pptx \[short slides\]] {{ [summary]

}} Lijie Chen, [https://sites.google.com/view/badihghazi/home Badih Ghazi], [https://sites.google.com/site/ravik53/ Ravi Kumar], [https://pasin30055.github.io/ Pasin Manurangsi]. /Innovations in Theoretical Computer Science/ (ITCS 2021)\n == [papersYear.html *Full Publications*]\n