Ariel Neufeld

Ariel Neufeld
Assistant Professor

Nanyang Technological University (NTU)
Division of Mathematical Sciences
Office SPMS-MAS 05-02
21 Nanyang Link
Singapore 637371
Phone (65) 6592 1799

I am a Nanyang Assistant Professor in mathematics at the Nanyang Technological University in Singapore.
I received my PhD from ETH Zurich in 2015 under the supervision of Prof. Marcel Nutz and Prof. Martin Schweizer.

My research focuses on:

• machine learning algorithms, their convergence rates, and their applications in finance and insurance
• model uncertainty in financial markets
• financial and insurance mathematics
• stochastic analysis and stochastic optimal control
• stochastic optimization and applied probability theory

Support by the NAP Grant, the MOE AcRF Tier 1 Grant RG74/21, and the Grant NRF2021-QEP2-02-P06 is gratefully acknowledged.

A detailed CV can be found here.

Open Positions

I am looking for Postdocs, PhD students, as well as Bachelor/Master students who would like to join my research group; see for example

Postdoc position

PhD position

Research Internship position

If you would like to join my research group (even if you do not see a suitable job announcement), please feel free to contact me anytime by email.

Members of the Research Group

Zeyi Chen   (Undergraduate Research Student, started 08.2022)

Matthew Ng Cheng En   (Project Officer, started 08.2021)

Thi Van Hang Nguyen   (Postdoctoral Research Fellow, SASEA Fellowship, starting 10.2022)

Philipp Schmocker   (PhD Student, started 08.2021)

Sizhou Wu   (Postdoctoral Research Fellow, started 08.2021)

Qikun Xiang   (PhD Student, started 08.2019)

Ying Zhang   (Postdoctoral Research Fellow, started 11.2020)

Former Members of the Research Group

Géraldine Bouveret   (Gopalakrishnan - Presidential Postdoctoral Fellow, 11.2019-01.2022; now Chief Research Officer at RIMM Sustainability)

Pushpendu Ghosh   (Research Internship, 08.2019-12.2019; now Applied Scientist at Amazon)

Yongming Li   (Project Officer, 05.2020-12.2020; now PhD student in mathematics at Texas A&M University)

Julian Sester   (Postdoctoral Research Fellow, 04.2020-06.2022; now Peng Tsu Ann Assistant Professor in mathematics at NUS)

Shunan Sheng   (Undergraduate Research Student, 06.2020-07.2022; now PhD student in statistics at Columbia University)

Daiying Yin   (Undergraduate Research Student, 06.2020-08.2021; now PhD student in mathematics at NTU with J.-P. Ortega)


Stochastic Processes MH 3512

Indicator Function
Conditional Expectation
Monotone Convergence & Dominated Convergence Theorem
Lecture notes (many thanks to N. Privault)
Lecture notes (same, but marked)

Publications and Preprints

A. Neufeld, P. Schmocker:
Chaotic Hedging with Iterated Integrals and Neural Networks
Preprint (submitted), 2022 [PDF, arXiv, Code]

A. Neufeld, M. Ng, Y. Zhang:
Non-asymptotic convergence bounds for modified tamed unadjusted Langevin algorithm in non-convex setting
Preprint (submitted), 2022 [PDF, arXiv, Code]

A. Neufeld, J. Sester, M. Sikic:
Markov Decision Processes under Model Uncertainty
Preprint (submitted), 2022 [PDF, arXiv, Code]

A. Neufeld, S. Wu:
Multilevel Picard approximation algorithm for semilinear partial integro-differential equations and its complexity analysis
Preprint (submitted), 2022 [PDF, arXiv]

A. Neufeld, Q. Xiang:
Numerical method for approximately optimal solutions of two-stage distributionally robust optimization with marginal constraints
Preprint (submitted), 2022 [PDF, arXiv, Code]

S. Sheng, Q. Xiang, I. Nevat, A. Neufeld:
Binary Spatial Random Field Reconstruction from Non-Gaussian Inhomogeneous Time-series Observations
Preprint (submitted), 2022 [PDF, arXiv, Code]

J. Ansari, E. Lütkebohmert, A. Neufeld, J. Sester:
Improved Robust Price Bounds for Multi-Asset Derivatives under Market-Implied Dependence Information
Preprint (submitted), 2022 [PDF, arXiv, Code]

A. Neufeld, J. Sester, D. Yin:
Detecting data-driven robust statistical arbitrage strategies with deep neural networks
Preprint (submitted), 2022 [PDF, arXiv, Code]

A. Neufeld, Q. Xiang:
Numerical method for feasible and approximately optimal solutions of multi-marginal optimal transport beyond discrete measures
Preprint (submitted), 2022 [PDF, arXiv, Code]

D.-Y. Lim, A. Neufeld, S. Sabanis, Y. Zhang:
Non-asymptotic estimates for TUSLA algorithm for non-convex learning with applications to neural networks with ReLU activation function
Preprint (submitted), 2021 [PDF, arXiv, Code]

A. Neufeld, J. Sester:
A deep learning approach to data-driven model-free pricing and to martingale optimal transport
Preprint (submitted), 2021 [PDF, arXiv, Code]

Q. Xiang, A. Neufeld, G. W. Peters, I. Nevat, A. Datta:
A Bonus-Malus Framework for Cyber Risk Insurance and Optimal Cybersecurity Provisioning
Preprint (submitted), 2021 [PDF, arXiv, Code]

C. Beck, S. Becker, P. Cheridito, A. Jentzen, A. Neufeld:
Deep learning based numerical approximation algorithms for stochastic partial differential equations and high-dimensional nonlinear filtering problems
Preprint (submitted), 2020 [PDF, arXiv, Code]

A. Neufeld, A. Papapantoleon, Q. Xiang:
Model-free bounds for multi-asset options using option-implied information and their exact computation
Management Science, 2022 [PDF, arXiv, DOI, Code]

P. Ghosh, A. Neufeld, J. K. Sahoo:
Forecasting directional movements of stock prices for intraday trading using LSTM and random forests
Finance Research Letters, Vol. 46, Part A, 102280, 2022 [PDF, arXiv, DOI, Code]

M. Baes, C. Herrera, A. Neufeld, P. Ruyssen:
Low-Rank plus Sparse Decomposition of Covariance Matrices using Neural Network Parametrization
IEEE Transactions on Neural Networks and Learning Systems, 2021 [PDF, arXiv, DOI, Code]

A. Neufeld, J. Sester:
On the stability of the martingale optimal transport problem: A set-valued map approach
Statistics & Probability Letters, Vol. 176, pp. 109131-1-7, 2021 [PDF, arXiv, DOI]

A. Neufeld, J. Sester:
Model-free price bounds under dynamic option trading
SIAM Journal on Financial Mathematics (SIFIN), Vol. 12, No. 4, pp. 1307-1339, 2021 [PDF, arXiv, DOI, Code]

D. Bartl, M. Kupper, A. Neufeld:
Duality Theory for Robust Utility Maximisation
Finance and Stochastics, Vol. 25, No. 3, pp. 469-503, 2021 [PDF, arXiv, DOI]

P. J. Graber, V. Ignazio, A. Neufeld:
Nonlocal Bertrand and Cournot Mean Field Games with General Nonlinear Demand Schedule
Journal de Mathématiques Pures et Appliquées (JMPA), Vol. 148, pp. 150-198, 2021 [PDF, arXiv, DOI]

P. Harms, C. Liu, A. Neufeld:
Supermartingale Deflators in the Absence of a Numéraire
Mathematics and Financial Economics, Vol. 15, pp. 885-915, 2021 [PDF, arXiv, DOI]

C. Beck, S. Becker, P. Cheridito, A. Jentzen, A. Neufeld:
Deep splitting method for parabolic PDEs
SIAM Journal on Scientific Computing (SISC), Vol. 43, No. 5, pp. A3135-A3154, 2021 [PDF, arXiv, DOI, Code]

A. Jentzen, B. Kuckuck, A. Neufeld, P. von Wurstemberger:
Strong error analysis for stochastic gradient descent optimization algorithms
IMA Journal of Numerical Analysis, Vol. 41, No. 1, pp. 455-492, 2021 [PDF, arXiv, DOI]

D. Bartl, M. Kupper, A. Neufeld:
Pathwise superhedging on prediction sets
Finance and Stochastics, Vol. 24, No. 1, pp. 215-248, 2020 [PDF, arXiv, DOI]

T. Fadina, A. Neufeld, T. Schmidt:
Affine processes under parameter uncertainty
Probability, Uncertainty and Quantitative Risk, Vol. 4, No. 1, pp. 1-35, 2019 [PDF, arXiv, DOI]

D. Bartl, M. Kupper, A. Neufeld:
Stochastic integration and differential equations for typical paths
Electronic Journal of Probability, Vol. 24, No. 97, pp. 1-21, 2019 [PDF, arXiv, DOI]

A. Neufeld, M. Sikic:
Nonconcave Robust Optimization with Discrete Strategies under Knightian Uncertainty
Mathematical Methods of Operations Research, Vol. 90, No. 2, pp. 229-253, 2019 [PDF, arXiv, DOI]

C. Liu, A. Neufeld:
Compactness Criterion for Semimartingale Laws and Semimartingale Optimal Transport
Transactions of the American Mathematical Society, Vol. 372, No. 1, pp. 187-231, 2019 [PDF, arXiv, DOI]

A. Neufeld:
Buy-and-Hold Property for Fully Incomplete Markets when Super-replicating Markovian Claims
International Journal of Theoretical and Applied Finance, Vol. 21, No. 8, 1850051, 2018 [PDF, arXiv, DOI]

A. Neufeld, M. Sikic:
Robust Utility Maximization in Discrete-Time Markets with Friction
SIAM Journal on Control and Optimization (SICON), Vol. 56, No. 3, pp. 1912-1937, 2018 [PDF, arXiv, DOI]

Y. Dolinsky, A. Neufeld:
Super-replication in Fully Incomplete Markets
Mathematical Finance, Vol. 28, No. 2, pp. 483-515, 2018 [PDF, arXiv, DOI]

A. Neufeld, M. Nutz:
Robust Utility Maximization with Lévy Processes
Mathematical Finance, Vol. 28, No. 1, pp. 82-105, 2018 [PDF, arXiv, DOI]

A. Neufeld, M. Nutz:
Nonlinear Lévy Processes and their Characteristics
Transactions of the American Mathematical Society, Vol. 369, No. 1, pp. 69-95, 2017 [PDF, arXiv, DOI]

A. Neufeld, M. Nutz:
Measurability of Semimartingale Characteristics with Respect to the Probability Law
Stochastic Processes and their Applications, Vol. 124, No. 11, pp. 3819-3845, 2014 [PDF, arXiv, DOI]

A. Neufeld, M. Nutz:
Superreplication under Volatility Uncertainty for Measurable Claims
Electronic Journal of Probability, Vol. 18, No. 48, pp. 1-14, 2013 [PDF, arXiv, DOI]

K. Du, A. Neufeld:
A note on asymptotic exponential arbitrage with exponentially decaying failure probability
Journal of Applied Probability, Vol. 50, No. 3, pp. 801-809, 2013 [PDF, arXiv, DOI]


A. Neufeld:
Knightian Uncertainty in Mathematical Finance
PhD Thesis ETH Zurich, Diss. ETH No. 22605, 2015 [PDF, ETH e-collection]


The Oracle of DLPhi [PDF]

This manuscript has mostly humouristic value. However, while the main theorem is based on a dubious application of the axiom of choice, it is a correct mathematical statement.
Therefore, this manuscript at least highlights the dangers of applying mathematical theory to real-world applications blindly.

Last update: September 22, 2022