http://www-math.umd.edu/research/seminars.html http://www-math.umd.edu/research/seminars.html Wed, 03 Sep 2025 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: () -

]]> http://www-math.umd.edu/research/seminars.html Fri, 05 Sep 2025 16:00:00 EDT Where: Kirwan Hall 3206
Speaker: Owen Patashnick (Kings College London) - https://www.kcl.ac.uk/people/owen-patashnick
Abstract:  In this talk, we will show that an analogy for a result about the action of the automorphism group on the mod p points of the Markoff surface is true for a certain class of K3 surfaces as well, namely, the Kummer of the square of an elliptic curve without CM.
]]> http://www-math.umd.edu/research/seminars.html Mon, 08 Sep 2025 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: Eric Jovinelly (Brown University) -
Abstract: Rational curves are intricately linked to the birational geometry of varieties containing them. Certain curves, called free curves, have the nicest deformation properties. However, it is unknown whether mildly singular Fano varieties contain free rational curves in their smooth locus. In this talk, we discuss free curves of higher genus. Using recent results about tangent bundles, we prove that any klt Fano variety has higher genus free curves. We then use the existence of such free curves to get some applications: we prove the existence of free rational curves in terminal Fano threefolds; obtain an optimal upper bound on the length of extremal rays in the Kleiman-Mori cone of any klt pair; and study the fundamental group of the smooth locus of a Fano variety. This is joint work with Brian Lehmann and Eric Riedl.

]]> http://www-math.umd.edu/research/seminars.html Mon, 15 Sep 2025 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: Patrick Lei (Boston College) -
Abstract: In this talk, I will outline some structural predictions from physics about the higher-genus Gromov-Witten theory of Calabi-Yau threefolds. Then I will explain some aspects of a proof of some of these conjectures for some targets which arise as hypersurfaces in weighted projective space using the master space approach (called mixed spin p-fields) of Chang-Guo-Li-Li-Liu.

]]> http://www-math.umd.edu/research/seminars.html Wed, 22 Oct 2025 14:00:00 EDT Where: Kirwan Hall 1311
Speaker: Trevor Jones (Johns Hopkins University) -
Abstract: A branchvariety of a projective k-scheme X is a geometrically reduced scheme Y equipped with a finite map to X. Alexeev and Knutson showed the existence of a proper moduli space of branchvarieties with fixed numerical invariants, but the projectivity of this space remained an open question. In this talk, we will discuss positivity results for certain line bundles on the moduli space of equidimensional branchvarieties. As a consequence, we establish that this moduli space is projective.
]]> http://www-math.umd.edu/research/seminars.html Mon, 27 Oct 2025 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: Yeqin Liu (University of Michigan) - https://public.websites.umich.edu/~yqnl/

Abstract: For a smooth projective variety, its bounded derived category of coherent sheaves can often be decomposed into smaller pieces, which are called semi-orthogonal components. It was once believed in the literature that additive invariants (e.g. Grothendieck group, Hochschild homology, ...) detect these components. In recent years, examples were found where all additive invariants of a semi-orthogonal component vanish, and such a component is called a phantom category. It was wondered if any phantom category admits a t-structure, which is a useful structure analogous to an abelian category embedded inside its derived category.
In this talk, I will give a general introduction to phantom categories, and show that there are no Noetherian or Artinian t-structures on them. I will explain the key idea by an intuitive example, and talk about potential future questions.
]]> http://www-math.umd.edu/research/seminars.html Mon, 17 Nov 2025 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Michael Temkin (Einstein Institute of Mathematics) - https://ma.huji.ac.il/~temkin/

]]> http://www-math.umd.edu/research/seminars.html Mon, 24 Nov 2025 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Erik Paemurru (Bulgarian Academy of Science) - https://erik.paemurru.com/
Abstract: We generalize an intersection-theoretic local inequality of Fulton-Lazarsfeld to weighted blowups. Using this together with the classification of 3-dimensional divisorial contractions, we prove nonrationality of many families of terminal Fano 3-folds. This is joint work with Igor Krylov and Takuzo Okada.
]]> http://www-math.umd.edu/research/seminars.html Mon, 01 Dec 2025 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Minh-Tam Trinh (Howard University) - https://mqtrinh.github.io/about/
Abstract: The Oblomkov–Rasmussen–Shende conjecture relates the Hilbert schemes of a plane curve singularity to a skein-theoretic invariant of its link, called its triply-graded HOMFLYPT homology. Oscar Kivinen and I discovered a more tractable analogue, in which the Hilbert schemes are replaced by other punctual Quot schemes. This led us to conjecture a mysterious motivic substitution relating the two families of varieties. I will survey this research program, as well as current work-in-progress where I expect to prove the full Quot conjecture for all sufficiently generic singularities. If time permits, I will explain what this program tells us about affine Springer fibers and other moduli spaces in representation theory.
]]> http://www-math.umd.edu/research/seminars.html Wed, 03 Dec 2025 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Siddarth Kannan (MIT) - https://sites.google.com/view/siddarthkannan
Abstract: I will discuss a combinatorially defined blow-up of the moduli space of curves in genus g
]]> http://www-math.umd.edu/research/seminars.html Wed, 04 Feb 2026 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Kimoi Kemboi (Princeton University) -
Abstract: A smooth cubic fourfold gives rise to two kinds of hyperkähler fourfolds: one is classical --the variety of lines on the cubic; and the other is "non-commutative" --arising from the symmetric square of the Kuznetsov component. Galkin conjectured that these two objects should be derived equivalent. In this talk, I’ll explain a proof of this conjecture, which uses matrix factorizations and a wall-crossing derived equivalence for a particular 12-dimensional flop. This is joint work with Ed Segal.
]]> http://www-math.umd.edu/research/seminars.html Wed, 18 Feb 2026 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Zinovy Reichstein (UBC) -
https://personal.math.ubc.ca/~reichst/
Abstract:  The Cremona dimension of a finite group G is the minimal dimension of a rationally connected variety which admits a faithful action of G.  In this talk, based on joint work with Giulio Bresciani and Angelo Vistoli, I will discuss new lower bounds on the Cremona dimension of a finite p-group.
]]> http://www-math.umd.edu/research/seminars.html Mon, 23 Feb 2026 14:00:00 EST Where: Kirwan Hall 3206
Speaker: Yilong Zhang (UGA) -

Title: Failure of the invariant cycle theorem over integers
Abstract: The invariant cycle theorem was proved by Clemens and Schmid in 70's. It compares the cohomology of the total space of a family of complex varieties with that of a general smooth fiber, asserting that the restriction map surjects onto the invariant part when working with rational coefficients. A natural question is whether the theorem still holds over integral coefficients. Positive cases are known, for example, for semistable families of K3 surfaces, which is due to Friedman in 80's. In a joint work with Arapura and Greer, we construct a counterexample over integral coefficients, given by a family of elliptic surfaces with p_g=q=1. Our construction generalizes the Shioda–Inose construction for rational double covers of K3 surfaces.
]]> http://www-math.umd.edu/research/seminars.html Wed, 11 Mar 2026 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: János Kollár (Princeton University ) -
https://web.math.princeton.edu/~kollar/
Abstract:  We show that a compact, complex analytic space X has a bimeromorphic orbifold modification that is an isomorphism over the locally trivial orbifold locus of X. (joint with Wenhao Ou)
]]> http://www-math.umd.edu/research/seminars.html Mon, 23 Mar 2026 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: Nikon Kurnosov (UCL) - https://users.mccme.ru/nikon/
Abstract: In this talk we will discuss the deformations of holomorphically symplectic manifolds which keep the subvarieties to be Lagrangian. This was first studied by Voisin who proved that for smooth subvarieties in hyperkahler manifolds that these deformations are exactly ones which keep subvariety complex. Later C. Lehn extended her approach to the snc subvarieties. We will outline the differences in non-Kahler case and study the deformations of C-symplectic structures, which work for large classes of Kahler and non-Kahler manifolds, and the Lagrangian subvarieties of a Kummer-type. Based on joint works with M.Verbitsky.
]]> http://www-math.umd.edu/research/seminars.html Wed, 08 Apr 2026 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: Jack Huizenga (Penn State University) - https://sites.psu.edu/jhuizenga/
Abstract: The Brill-Noether theory of curves plays a fundamental role in the theory of curves and their moduli and has been intensively studied since the 19th century. In contrast, Brill-Noether theory for vector bundles and higher dimensional varieties is less understood. It is hard to determine when Brill-Noether loci are nonempty and these loci can be reducible and of larger than the expected dimension.
In this talk, we will study Brill-Noether loci for vector bundles on the projective plane in the case where the number of sections is close to the largest possible number.  When the number of sections is very large, Brill-Noether problems are all "trivial"--the Brill-Noether loci are either empty or the entire moduli space.  As the number of sections decreases, we find that there is a "first" nontrivial Brill-Noether locus, and we discuss its geometry.
]]> http://www-math.umd.edu/research/seminars.html Wed, 06 May 2026 14:00:00 EDT Where: Kirwan Hall 3206
Speaker: Giovanni Inchiostro (University of Washington) - https://sites.math.washington.edu/~ginchios/
Abstract: I will present two different compactifications of the moduli space of surfaces fibered in log Calabi-Yau pairs, coming from a generalization of quasimap theory and from KSBA-stability. This is based on a series of joint works, with Andrea Di Lorenzo; Roberto Svaldi and Junyan Zhao
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