Research
My research interests lie in commutative algebra, algebraic geometry, and combinatorics, focusing on multiplicity theory and its applications in algebraic, geometric, and combinatorial structures. My work revolves around several key themes:
- Multiplicities, Integral Dependence and Equisingularity.
- Multiplicities, Edge Ideals and Edge Polytopes of Graphs.
- Inequalities for Multiplicities.
- Symbolic Powers of Ideals.
- Syzygies and Singularities.
The theory of multiplicities, centuries old, involves a rich interplay of ideas from various fields, including algebraic geometry, commutative algebra, convex geometry, and combinatorics. The first rigorous general algebraic treatment of multiplicities was given by Chevalley and Samuel for zero-dimensional ideals, and they soon became ubiquitous in commutative algebra. For instance, the Hilbert-Samuel multiplicity plays a prominent role in the theory of integral dependence of ideals due to the influential work of Rees.
Multiplicity theory also has close ties with polyhedral geometry through Ehrhart theory. For example, the Hilbert-Samuel multiplicity of a zero-dimensional monomial ideal equals the normalized full-dimensional volume of the complement of its Newton polyhedron in the positive orthant.
More recently, Achilles and Manaresi introduced the concept of j-multiplicity for ideals, and with B. Ulrich, we proposed the notion of ε-multiplicity, extending the classical Hilbert-Samuel multiplicity to arbitrary ideals and modules in a general algebraic setting. In a series of papers with various collaborators, we have proved these invariants valuable in commutative algebra, algebraic geometry, and combinatorics for their connections to the theory of integral closures, Rees valuations, equisingularity theory, and graph theory.
Collaborators
Over the years, I have had the privilege of working with leading experts from diverse fields. Below is a partial list of my collaborators and their respective institutions.
- Neil Epstein, George Mason University
- Craig Huneke, University of Virginia
- Daniel Katz, University of Kansas
- Youngsu Kim, California State University, San Bernardino
- Steven Kleiman, MIT
- Claudia Polini, University of Notre Dame
- Alexandra Seceleanu, University of Nebraska-Lincoln
- Hal Schenck, Auburn University
- Ilya Smirnov, KTH Royal Institute of Technology
- Ivan Soprunov, Cleveland State University
- Ngo Viet Trung, Vietnam Academy of Science and Technology
- Bernd Ulrich, Purdue University