Benjamin Merlin Bumpus
Benjamin Merlin Bumpus was a faculty research scientist and led the algorithms subproject within the GATAS Lab.
In 2023 he accepted a professorship at the Institute of Mathematics, Statistics, and Computer Science (IME) at the University of São Paulo (USP) in Brazil, where he now heads the CombTheta research group and the CUÍCA (Categorical Understanding in Computation and Algorithms) lab. He has kept working with the lab and with groups across South America and Europe on categorical methods in computational complexity and graph theory: most recently the Brazilian Category Theory Conference and our paper on temporal data with sheaves.
Ben’s research focuses on the emergence of complexity and its relationship to compositionality—the principle that the structure or meaning of a whole depends on that of its parts. He investigates computational complexity, combinatorial explosion, and their connections to graph structure theory, parameterized complexity, and finite model theory, using category theory to relate and generalize tools across these areas.
Ben introduced sheaf theory to the GATAS Lab, initially to characterize fixed-parameter tractable algorithms and dynamic programming categorically. It is how the lab came to think in terms of local data and the conditions under which it glues, where before the question had been how monoidal functors interact with colimits.
Selected publications
- Towards a Unified Theory of Time-Varying Data – Applied Categorical Structures, 2026. Benjamin Merlin Bumpus, Wilmer Leal, James Fairbanks, Martti Karvonen, Frédéric Simard. DOI: 10.1007/s10485-026-09860-4
- How nice is this functor? Two squares and some homology go a long way – Applied Category Theory (ACT 2024). Benjamin Merlin Bumpus, James Fairbanks, Fabrizio Genovese, Caterina Puca, Daniel Rosiak.
- Algorithmic and Extremal Obstructions Through the Language of Cohomology – 2025. Anny Beatriz Azevedo, Benjamin Merlin Bumpus, Matteo Capucci, James Fairbanks, Daniel Rosiak. arXiv:2407.03488
- Lassos: Pushing Tree Decompositions Forward Along Homomorphisms – 2024. Benjamin Merlin Bumpus, James Fairbanks, Will J. Turner. arXiv:2408.15184
- Compositional Algorithms on Compositional Data: Deciding Sheaves on Presheaves – 2023. Ernst Althaus, Benjamin Merlin Bumpus, James Fairbanks, Daniel Rosiak. arXiv:2302.05575
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