Zack Fitzsimmons


Haberlin 310
College of the Holy Cross
One College Street
Worcester, MA 01610
Phone: (508) 793-2546
Email: zfitzsim at holycross.edu
ORCID: 0000-0001-5147-9646

About Me:


I'm an Associate Professor of Computer Science and the Computer Science Program Coordinator at the College of the Holy Cross. I completed my Ph.D. in Computing and Information Sciences at the Rochester Institute of Technology and my B.S. in Computer Science and Mathematics at Siena College. My research interests are in computational social choice, focusing on the hardness of manipulative attacks on elections, and domain restrictions.

Current Courses (Spring 2025):


Office Hours (Spring 2025):

  • Tuesday, 3:30 PM–5:00 PM
  • Thursday, 3:30 PM–5:00 PM
  • Friday, 1:00 PM–2:00 PM
  • By appointment.

Previous Courses:

  • Techniques of Programming (CSCI 131), Spring 2019, Fall 2020 (Lab), Fall 2021 (Lab).
  • Data Structures (CSCI 132), Fall 2017, Spring 2018, Spring 2020, Fall 2020, Spring 2021 (Lab), Fall 2021, Spring 2022, Fall 2022, Spring 2023, Fall 2024.
  • Discrete Structures (CSCI 135), Spring 2021.
  • Analysis of Algorithms (CSCI 235), Fall 2018.
  • Programming Languages: Design and Implementation (CSCI 324), Spring 2022.
  • Theory of Computation (CSCI 345), Spring 2018, Spring 2020, Fall 2021, Fall 2024.
  • Artificial Intelligence (CSCI 347), Fall 2018 (as CSCI 399), Fall 2020, Fall 2022.

Previous Courses (RIT):

  • Introduction to Cryptography (CSCI 462), Fall 2016.
  • Foundations of Computer Science Theory (CSCI 660), Intersession 2015.
  • Foundations of Computer Science Theory (CSCI 660), Intersession 2014.

Journal Publications:

  • Z. Fitzsimmons, E. Hemaspaandra, and L. Hemaspaandra. Control in the Presence of Manipulators: Cooperative and Competitive Cases. Autonomous Agents and Multi-Agent Systems, 34(52): 1-32, 2020. PDF
  • Z. Fitzsimmons and M. Lackner. Incomplete Preferences in Single-Peaked Electorates. Journal of Artificial Intelligence Research, 67: 797-833, 2020. PDF
  • Z. Fitzsimmons and E. Hemaspaandra. High-Multiplicity Election Problems. Autonomous Agents and Multi-Agent Systems, 33(4): 383-402, 2019. PDF
  • Z. Fitzsimmons, E. Hemaspaandra, and L. Hemaspaandra. Manipulation Complexity of Same-System Runoff Elections. Annals of Mathematics and Artificial Intelligence, 77(3-4): 159-189, 2016. PDF
  • Z. Fitzsimmons and R. Flatland. Algorithms for Collective Construction of 2D Block Structures with Holes. American Journal of Undergraduate Research, 10(2):1-10, 2011. PDF

Conference Publications:

  • Z. Fitzsimmons, V. Viswanathan, and Y. Zick. On the Hardness of Fair Allocation under Ternary Valuations. In Proceedings of the 24th International Conference on Autonomous Agents and Multiagent Systems, May 2025, Detriot, MI. To appear. arXiv
  • Z. Fitzsimmons and E. Hemaspaandra. Using Weighted Matching to Solve 2-Approval/Veto Control and Bribery. In Proceedings of the 26th European Conference on Artificial Intelligence, October 2023, pages 732-739, Krakow, Poland. arXiv
  • Z. Fitzsimmons and E. Hemaspaandra. Complexity of Conformant Election Manipulation. In Proceedings of the 24th International Symposium on Fundamentals of Computation Theory, pages 176-189, September 2023, Trier, Germany. arXiv
  • Z. Fitzsimmons and E. Hemaspaandra. Insight into Voting Problem Complexity Using Randomized Classes. In Proceedings of the 31st International Joint Conference on Artificial Intelligence, pages 293-299, July 2022, Vienna, Austria. arXiv
  • Z. Fitzsimmons and E. Hemaspaandra. Kemeny Consensus Complexity. In Proceedings of the 30th International Joint Conference on Artificial Intelligence, pages 196-202, August 2021, Montreal, Canada. PDF
  • E. Anshelevich, Z. Fitzsimmons, R. Vaish, and L. Xia. Representative Proxy Voting. In Proceedings of the 35th AAAI Conference on Artificial Intelligence, pages 5086-5093, February 2021, Vancouver, Canada. PDF
  • Z. Fitzsimmons and O. Lev. Selecting Voting Locations for Fun and Profit. In Proceedings of the 29th International Joint Conference on Artificial Intelligence, pages 224-230, July 2020, Yokohama, Japan. PDF
    • Also appears in Workshop Notes of the 12th Multidisciplinary Workshop on Advances in Preference Handling, August 2020, Santiago de Compostela, Spain. Slides.
  • Z. Fitzsimmons and E. Hemaspaandra. Election Score Can Be Harder Than Winner. In Proceedings of the 24th European Conference on Artificial Intelligence, pages 83-90, August/September 2020, Santiago de Compostela, Spain. PDF
    • Also appears in Workshop Notes of the 8th International Workshop on Computational Social Choice, June 2021, Haifa, Israel.
  • Z. Fitzsimmons, E. Hemaspaandra, A. Hoover, and D. Narváez. Very Hard Electoral Control Problems. In Proceedings of the 33rd AAAI Conference on Artificial Intelligence, pages 1933-1940, January/February 2019, Honolulu, HI. PDF
    • Also appears in Workshop Notes of the 7th International Workshop on Computational Social Choice, June 2018, Troy, NY and in Workshop Notes of the AAMAS-IJCAI Workshop on Agents and Incentives in Artificial Intelligence, July 2018, Stockholm, Sweden.
  • Z. Fitzsimmons and E. Hemaspaandra. High-Multiplicity Election Problems. In Proceedings of the 17th International Conference on Autonomous Agents and Multiagent Systems, pages 1558-1566, July 2018, Stockholm, Sweden. PDF
    • Also appears in Workshop Notes of the 7th International Workshop on Computational Social Choice, June 2018, Troy, NY.
  • Z. Fitzsimmons and E. Hemaspaandra. The Complexity of Succinct Elections. In Proceedings of the 31st AAAI Conference on Artificial Intelligence (Student Abstract), pages 4921-4922, February 2017, San Francisco, CA. PDF
  • Z. Fitzsimmons and E. Hemaspaandra. Modeling Single-Peakedness for Votes with Ties. In Proceedings of the 8th European Starting AI Researcher Symposium, pages 63-74, August 2016, The Hague, The Netherlands. PDF
    • Also appears in Workshop Notes of the 10th Multidisciplinary Workshop on Advances in Preference Handling, July 2016, New York, NY.
  • Z. Fitzsimmons and E. Hemaspaandra. Complexity of Manipulative Actions When Voting with Ties. In Proceedings of the 4th International Conference on Algorithmic Decision Theory, pages 103-119, September 2015, Lexington, KY. PDF
    • Also appears in Workshop Notes of the 6th International Workshop on Computational Social Choice, June 2016, Toulouse, France.
  • Z. Fitzsimmons Single-Peaked Consistency for Weak Orders Is Easy. In Proceedings of the 15th Conference on Theoretical Aspects of Rationality and Knowledge, pages 127-140, June 2015, Pittsburgh, PA. PDF
  • Z. Fitzsimmons. Realistic Assumptions for Attacks on Elections. In Proceedings of the 29th AAAI Conference on Artificial Intelligence (Doctoral Consortium), pages 4235-4236, January 2015, Austin, TX. PDF
  • Z. Fitzsimmons, E. Hemaspaandra, and L. Hemaspaandra. Control in the Presence of Manipulators: Cooperative and Competitive Cases. In Proceedings of the 23rd International Joint Conference on Artificial Intelligence, pages 113-119, August 2013, Beijing, China. PDF
    • Also appears in Workshop Notes of the 5th International Workshop on Computational Social Choice, June 2014, Pittsburgh, PA.
  • A. Joginpelly, A. Varela, D. Charalampidis, R. Schott, and Z. Fitzsimmons. Efficient FPGA Implementation of Steerable Gaussian Smoothers. In Proceedings of the 44th Southeastern Symposium on System Theory, pages 78-82, March 2012, Jacksonville, FL. PDF