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A local normal form theorem for smooth equivariant maps between Fr\'echet manifolds is established. Moreover, an elliptic version of this theorem is obtained. The proof these normal form results is inspired by the Lyapunov-Schmidt reduction…

Symplectic Geometry · Mathematics 2019-09-04 Tobias Diez

We give a systematic construction of semiorthogonal decompositions of derived categories of coherent sheaves on quasi-smooth derived algebraic stacks over $\mathbb{C}$, where the summands are subcategories defined by weight conditions, and…

Algebraic Geometry · Mathematics 2026-05-26 Chenjing Bu , Tudor Pădurariu , Yukinobu Toda

Generalizing work of Smith and Hara, we give a new characterization of log-terminal singularities for finitely generated algebras over $\mathbb C$, in terms of purity properties of ultraproducts of characteristic $p$ Frobenii. The first…

Algebraic Geometry · Mathematics 2007-05-23 Hans Schoutens

We define Gromov--Witten invariants of exploded manifolds. The technical heart of this paper is a construction of a virtual fundamental class $[\mathcal K]$ of any Kuranishi category $\mathcal K$ (which is a simplified, more general version…

Symplectic Geometry · Mathematics 2019-06-26 Brett Parker

Let \(\T\) be a commutative ternary \(\Gm\)-semiring in the sense of the triadic, \(\Gm\)-parametrized multiplication \(\{a,b,c\}_{\gamma}\). Building on the affine \(\Gm\)-spectrum \(\SpecG(\T)\), the structure sheaf, and the equivalence…

Rings and Algebras · Mathematics 2025-12-30 Chandrasekhar Gokavarapu

We build actions of Thompson group V (related to the Cantor set) and of the so-called "spheromorphism" group of Neretin, on "towers" of moduli spaces of genus zero real stable curves. The latter consist of inductive limits of spaces which…

Group Theory · Mathematics 2007-05-23 Christophe Kapoudjian

We investigate the behavior of semi-orthogonal decompositions of bounded derived categories of singular varieties under flat deformations to smooth varieties. We consider a Q-Gorenstein smoothing of a surface with a quotient singularity,…

Algebraic Geometry · Mathematics 2024-10-22 Yujiro Kawamata

We remove the global quotient presentation input in the theory of windows in derived categories of smooth Artin stacks of finite type. As an application, we use existing results on flipping of strata for wall-crossing of Gieseker…

Algebraic Geometry · Mathematics 2014-12-16 Matthew Robert Ballard

We define Gromov-Witten classes and invariants of smooth projective schemes of finite presentation over a Dedekind domain. We prove that they are deformation invariants and verify the fundamental axioms. For a smooth projective scheme over…

Algebraic Geometry · Mathematics 2013-02-07 Flavia Poma

Perverse schobers are conjectural categorical analogs of perverse sheaves. We show that such structures appear naturally in Homological Minimal Model Program which studies the effect of birational transformations such as flops, on the…

Algebraic Geometry · Mathematics 2018-01-26 Alexey Bondal , Mikhail Kapranov , Vadim Schechtman

We construct the quasi-classical approximation of the form factors in finite volume using the separation of variables. The latter is closely related to the Baxter equation.

High Energy Physics - Theory · Physics 2007-05-23 Feodor A. Smirnov

Using the concept of a cohesive module defined by Block, we use the theory of superconnections in the sense of Quillen to construct natural superconnections on Hermitian cohesive modules. By the Chern-Weil construction, we obtain…

Differential Geometry · Mathematics 2016-11-15 Hua Qiang

In previous work, Mixed-Spin-P field has been introduced and their moduli space $\cal{W}_{g,\gamma,\bf{d}}$ together with a $\mathbb{C}^*$ action is constructed. Applying virtual localization to their virtual classes…

Algebraic Geometry · Mathematics 2017-08-10 Huai-Liang Chang , Jun Li

We use techniques from Gromov-Witten theory to construct new invariants of matroids taking value in the Chow groups of spaces of rational curves in the permutohedral toric variety. When the matroid is realizable by a complex hyperplane…

Algebraic Geometry · Mathematics 2022-05-03 Dhruv Ranganathan , Jeremy Usatine

A bootstrap procedure for functional time series is proposed which exploits a general vector autoregressive representation of the time series of Fourier coefficients appearing in the Karhunen-Lo\`eve expansion of the functional process. A…

Statistics Theory · Mathematics 2017-12-04 Efstathios Paparoditis

We introduce frameworks for constructing global derived moduli stacks associated to a broad range of problems, bridging the gap between the concrete and abstract conceptions of derived moduli. Our three approaches are via differential…

Algebraic Geometry · Mathematics 2014-11-11 J. P. Pridham

We develop a theory of \emph{reduced} Gromov-Witten and stable pair invariants of surfaces and their canonical bundles. We show that classical Severi degrees are special cases of these invariants. This proves a special case of the MNOP…

Algebraic Geometry · Mathematics 2016-05-10 M. Kool , R. P. Thomas

We introduce the notion of almost perfect obstruction theory on a Deligne-Mumford stack and show that stacks with almost perfect obstruction theories have virtual structure sheaves which are deformation invariant. The main components in the…

Algebraic Geometry · Mathematics 2019-12-12 Young-Hoon Kiem , Michail Savvas

We generalize the results of Chang-Li, Kim-Oh and Chang-Li on the moduli of $p$-fields to the setting of (quasi-)maps to complete intersections in arbitrary smooth Deligne-Mumford stacks with projective coarse moduli. In particular, we show…

Algebraic Geometry · Mathematics 2021-07-20 Qile Chen , Felix Janda , Rachel Webb

We consider the derived category of coherent sheaves on a complex vector space equivariant with respect to an action of a finite reflection group G. In some cases, including Weyl groups of type A, B, G_2, F_4, as well as the groups…

Algebraic Geometry · Mathematics 2017-06-07 Alexander Polishchuk , Michel Van den Bergh