Will Ma Assistant Professor Decision, Risk, and Operations (DRO) division Graduate School of Business, Columbia University Email: wm2428 (at) gsb (dot) columbia (dot) edu Office: Uris 407

Hi! I am an assistant professor in the Decision, Risk, and Operations division at Columbia Business School. Prior to July 2019, I was a postdoctoral researcher with the Operations Research group at Google Cambridge. In July 2018, I received my Ph.D. from the MIT Operations Research Center.

I spent 2013-2015 as a co-founder of Lunarch Studios, the start-up that designed the strategy game Prismata. During those years, I had also been a research intern with the Ad Exchange team at Google New York, and a trading intern at Jane Street Capital.

I completed my undergraduate degree in 2010 from the University of Waterloo, majoring in Pure Mathematics and Combinatorics/Optimization. During that time, I competed in many international poker tournaments. In 2011 I founded the annual poker class at MIT, which can be found on MIT OpenCourseWare.

Recent Working Papers

• When is Assortment Optimization Optimal?

  Management Science, under Major Revision

  *Finalist, Rothkopf Junior Researcher Paper Prize for Auctions and Market Design (TBA INFORMS 2021)

  *Selected for oral presentation in the INFORMS Market Design Workshop at EC, 2021

  *Selected for oral presentation in the MSOM Service SIG, 2021

  *Selected for oral presentation in the Market Innovation Workshop, 2021

• Tight Guarantees for Multi-unit Prophet Inequalities and Online Stochastic Knapsack with Jiashuo Jiang, Jiawei Zhang

  To appear in the Proceedings of the 33rd Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), 2022

  *Jiashuo Jiang is a Finalist in the Jeff McGill Student Paper Award for Revenue Management and Pricing (TBA INFORMS 2021)

• Tight Guarantees for Static Threshold Policies in the Prophet Secretary Problem with Nick Arnosti

• Improved Guarantees for Offline Stochastic Matching via new Ordered Contention Resolution Schemes with Brian Brubach, Nathaniel Grammel, Aravind Srinivasan

  To appear in the Proceedings of the 35th Conference on Neural Information Processing Systems (NeurIPS), 2021

• Optimizing for Strategy Diversity in the Design of Video Games with Oussama Hanguir, Christopher Thomas Ryan

• Fairness Maximization among Offline Agents in Online-Matching Markets with Pan Xu, Yifan Xu

  To appear in the Proceedings of the 17th Conference on Web and Internet Economics (WINE), 2021

Journal Articles

• Distributionally Robust Linear and Discrete Optimization with Marginals with Louis Chen, Karthik Natarajan, David Simchi-Levi, Zhenzhen Yan

  To appear in Operations Research

• Revenue-Optimal Deterministic Auctions for Multiple Buyers with Ordinal Preferences over Fixed-Price Items

  To appear in the ACM Transactions on Economics and Computation (TEAC)

  *Invited submission from the 16th Conference on Web and Internet Economics (WINE), 2020

• Inventory Balancing with Online Learning with Wang Chi Cheung, David Simchi-Levi, Xinshang Wang

  To appear in Management Science

• Dynamic Pricing (and Assortment) under a Static Calendar with David Simchi-Levi, Jinglong Zhao

  Management Science, 2021

• On Policies for Single-leg Revenue Management with Limited Demand Information with David Simchi-Levi, Chung-Piaw Teo

  Operations Research, 2021

• Algorithms for Online Matching, Assortment, and Pricing with Tight Weight-dependent Competitive Ratios with David Simchi-Levi

  Operations Research, 2020

  *Conference version, Tight Weight-dependent Competitive Ratios for Online Edge-weighted Bipartite Matching and Beyond, in Proceedings of the 20th ACM conference on Economics and Computation (EC), 2019

  *Finalist, George E. Nicholson Student Paper Competition, 2017

• Separation between Second Price Auctions with Personalized Reserves and the Revenue Optimal Auction with Balasubramanian Sivan

  Operations Research Letters, 2020

• Strong Mixed-Integer Programming Formulations for Trained Neural Networks with Ross Anderson, Joey Huchette, Christian Tjandraatmadja, Juan Pablo Vielma

  Math Programming, 2020

• Improvements and Generalizations of Stochastic Knapsack and Markovian Bandits Approximation Algorithms

  Mathematics of Operations Research, 2018

  *Conference version, Improvements and Generalizations of Stochastic Knapsack and Multi-armed Bandit Approximation Algorithms, in Proceedings of the 25th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), 2014

  *Honorable Mention, INFORMS Optimization Society Student Paper Competition, 2017

Under Revision/Review

• Assortment Planning for Recommendations at Checkout under Inventory Constraints with Xi Chen, David Simchi-Levi, Linwei Xin

  Mathematics of Operations Research, under 3rd Round Review

  *Covered in Chicago Booth Review, 2018

  *1st Place, Chinese Scholars Association for Management Science and Engineering (CSAMSE) Best Paper Award sponsored by Columbia Business School, 2017

  *2nd Place, POMS Hong Kong Student Paper Competition, 2017

• Bifurcating Constraints to Improve Approximation Ratios for Network Revenue Management with Reusable Resources with Jackie Baek

  Operations Research (Technical Note), under Minor Revision

  *Conference version, Prophet Inequalities on the Intersection of a Matroid and a Graph, in Proceedings of the 12th Symposium on Algorithmic Game Theory (SAGT), 2019

• Follow Your Star: New Frameworks for Online Stochastic Matching with Known and Unknown Patience with Brian Brubach, Nathaniel Grammel, Aravind Srinivasan

  Operations Research, under Major Revision

  *Conference version in Proceedings of the 24th International Conference on Artificial Intelligence and Statistics (AISTATS), 2021

• Constructing Demand Curves from a Single Observation of Bundle Sales with David Simchi-Levi

  Operations Research, under Major Revision

  *1st Place, INFORMS Data Mining Section Best Student Paper Competition---Applied Track, 2018

• Group-level Fairness Maximization in Online Bipartite Matching with Pan Xu, Yifan Xu

• A Competitive Analysis of Online Knapsack Problems with Unit Density with David Simchi-Levi, Jinglong Zhao

  *Jinglong Zhao earned an Honorable Mention in the POMS Hong Kong Student Paper Competition, 2020

• Multi-Stage and Multi-Customer Assortment Optimization With Inventory Constraints with Elaheh Fata, David Simchi-Levi

Other Refereed Conference Proceedings

• Reaping the Benefits of Bundling under High Production Costs with David Simchi-Levi

  Proceedings of the 24th International Conference on Artificial Intelligence and Statistics (AISTATS), 2021

• The Convex Relaxation Barrier, Revisited: Tightened Single-Neuron Relaxations for Neural Network Verification with Christian Tjandraatmadja, Ross Anderson, Joey Huchette, Krunal Patel, Juan Pablo Vielma

  Proceedings of the 34th Conference on Neural Information Processing Systems (NeurIPS), 2020

• Distributionally Robust Max Flows with Louis Chen, Jim Orlin, David Simchi-Levi

  Proceedings of the 3rd ACM-SIAM Symposium on Simplicity in Algorithms (SOSA), 2020

• A Geometric Approach to Combinatorial Fixed-point Theorems with Elyot Grant

  Proceedings of the 7th European Conference on Combinatorics, Graph Theory and Applications (EUROCOMB), 2013

• The Approximability and Integrality Gap of Interval Stabbing and Independence Problems with Shalev Ben-David, Elyot Grant, Malcolm Sharpe

  Proceedings of the 24th Canadian Conference on Computational Geometry (CCCG), 2012

• Packing and Covering Triangles in Planar Graphs with Qing Cui, Penny Haxell

  Graphs and Combinatorics, 2009