Nayel Bettache, PhD

About me

I am a Jacob Wolzfwitz Visiting Assistant Professor at Cornell University.

I hold a PhD in Mathematical Statistics from CREST and Institut Polytechnique de Paris. My supervisor was Cristina Butucea. My manuscript is available here and you can find the slides from the defense here.

My research delves into the foundational aspects of mathematical statistics and machine learning, placing a special emphasis on crafting practical and efficient learning methods with provable theoretical guarantees. I am particularly interested in time series, random matrix theory and high dimensional estimation problems.

Academic Appointments

• Visiting Assistant Professor, Cornell University, Department of Statistics and Datascience, Since Aug. 2024.
• Visiting Researcher, Harvard University, Invited by Tracy Ke, April 2023.
• Visiting Researcher, Cornell University, Invited by Florentina Bunea, May 2023.
• Graduate Researcher, CREST-ENSAE, Supervised by Cristina Butucea, Jan. 2023 - Aug. 2023.
• Research Intern, CREST-ENSAE, Supervised by Cristina Butucea, Jun. 2018 - Sep. 2018.

Education

• PhD. in Mathematical Statistics, Institut Polytechnique de Paris, Sep. 2021 - Jul. 2024.
• M.Sc Statistics and Learning, ENSAE IP Paris, Sep. 2017 - Jul. 2020.
• M.Sc DataScience, Ecole Polytechnique, Sep. 2019 - Jul. 2020.
• Classes Préparatoires MPSI-MP, Institution Aux Lazaristes, Sep. 2014 - Jul. 2017.

Publications

Preprints

• Bivariate Matrix-valued Linear Regression (BMLR): Finite-sample performance under Identifiability and Sparsity Assumptions.
  N.B.
  Preprint ArXiv, 2024.
  

Journal

• Low-rank regularization in two-sided matrix regression.
  N.B., C. Butucea.
  Accepted by Electronic Journal of Statistics (EJS) , 2025.
  
• Fast nonasymptotic testing and support recovery for large sparse Toeplitz covariance matrices .
  N.B, C.Butucea, M.Sorba
  Accepted by Journal of Multivariate Analysis (JMVA), 2022.

Teaching

Cornell University - Visiting Assistant Professor

• Statistical Methods II , STSCI 6020
  PhD Level - Fall 2024.
  Class Roster
• Introduction to R Programming, STSCI 2120/5120
  Undergraduate and Graduate - Fall 2024.
  Class Roster
• Data Mining and Machine Learning , STSCI 3740/5740
  Undergraduate and Graduate - Fall 2024.
  Class Roster

ENSAE - Teaching Assistant
Honored in the top 1% of teachers for exceptional pedagogical quality.

• Probability Theory -- Undergraduate (L3) - Professor: Victor-Emmanuel Brunel - Spring 2024 & 2023.
• Measure Theory -- Undergraduate (L3) - Professor: Cristina Butucea - Fall 2023 & 2022.
• Optimization -- Undergraduate (L3) - Professor: Guillaume Lecué - Spring 2023 & 2022.
• Machine Learning -- Graduate (M1) - Professor: Vianney Perchet - Spring 2022.
• Statistical Learning -- Graduate (M2) - Professor: Cristina Butucea - Fall 2021.
• Linear Algebra -- Undergraduate (L3) - Professor: Matthieu Lerasle - Fall 2021.
• Introduction to Statistics -- Undergraduate (L3) - Professor: Matthieu Lerasle - Spring 2021.
• Numerical Methods -- Undergraduate (L3) - Professor: Sidi Mahmoud Kaber - Spring 2021.

Nayel Prepa - Founder
Received a stellar 100% 5-star rating on Trustpilot.

• Founding a company democratising access to high-quality mathematics education for undergraduate students.
• Pioneering online live teaching sessions for 15+ undergraduate students at a time.
• Publishing 80 videos, garnered 6.5k subscribers and amassed over 250k views on Youtube.
• Training successfully 100+ students.

Grants

• Junior Scientific Visibility: Fondation Mathématique Jacques Hadamard, 2023 (2300€).
• PhD Grant: Genes, 2021-2024 (70k€).

Talks

• PhD Defense, Palaiseau (France), July 2024.
• European Meeting of Statisticians, Warsaw (Poland), July 2023.
• Harvard Stat 300 Seminar, Harvard University, Cambridge (MA, USA), May 2023.
• Second-year PhD student days, Ecole Doctorale Mathématiques Hadamard, Palaiseau (France), May 2022. Slides
• First-year PhD student days, Ecole Doctorale Mathématiques Hadamard, Palaiseau (France), May 2021. Slides

Conferences

• Meeting in Mathematical Statistics, Luminy (France), December 2024.
• Statistics and Learning Theory in the Era of Artificial Intelligence, Oberwolfach (Germany), June 2024.
• Meeting in Mathematical Statistics, Luminy (France), December 2023.
• European Meeting of Statisticians , Warsaw (Poland), July 2023.
• Jianqing Fan’s 60th Birthday Celebration, Princeton (NJ, USA), May 2023.
• Meeting in Mathematical Statistics, Luminy (France), December 2022.
• IMS Meeting, London (UK), June 2022.

Reviewing

• Latin American Journal of Probability and Mathematical Statistics (ALEA), 2022
• International Colloquium on Automata, Languages and Programming (ICALP), 2023

Industrial Experience

• Quantitative Research Intern, BNP Paribas (London), Under the supervision of Philippe Amzelek, Jul.2020 –Dec. 2020.
• Quantitative Research Intern, Advestis (Paris), Under the supervision of Christophe Geissler, Jun.2019-Oct. 2019.

Curriculum Vitae