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The titular, foundational work of Beilinson not only gives a technique for gluing perverse sheaves but also implicitly contains constructions of the nearby and vanishing cycles functors of perverse sheaves. These constructions are…

Algebraic Geometry · Mathematics 2010-07-13 Ryan Reich

Let $f : X\to \Delta$ be a $1$-parameter family of $2$-dimensional isolated hypersurface singularities. In this paper, we show that if the Milnor number is constant, then any semistable model, obtained from $f$ after a sufficiently large…

Algebraic Geometry · Mathematics 2023-12-05 Marta Aldasoro Rosales

We provide a description of Iwahori-Whittaker equivariant perverse sheaves on affine flag varieties associated to tamely ramified reductive groups, in terms of Langlands dual data. This extends the work of Arkhipov-Bezrukavnikov from the…

Representation Theory · Mathematics 2024-11-06 Rızacan Çiloğlu

For a set of sorts $S$ and an $S$-sorted signature $\Sigma$ we prove that a profinite $\Sigma$-algebra, i.e., a projective limit of a projective system of finite $\Sigma$-algebras, is a retract of an ultraproduct of finite $\Sigma$-algebras…

Category Theory · Mathematics 2018-08-27 Juan Climent Vidal , Enric Cosme Llópez

We find and describe unexpected isomorphisms between two very different objects associated to hypersurface singularities. One object is the Milnor algebra of a function, while the other object associated to a singularity is the local ring…

Algebraic Geometry · Mathematics 2008-04-10 Bernd Martin , Hendrik Süß

In the paper we introduce the notions of a singular fibration and a singular Seifert fibration. These notions are natural generalizations of the notion of a locally trivial fibration to the category of stratified pseudomanifolds. For…

Differential Geometry · Mathematics 2008-01-29 M. Saralegi-Aranguren , R. Wolak

A (compact) manifold with fibered $P$-singularities is a (possibly) singular pseudomanifold $M_\Sigma$ with two strata: an open nonsingular stratum $\mathring M$ (a smooth open manifold) and a closed stratum $\beta M$ (a closed manifold of…

Differential Geometry · Mathematics 2023-09-07 Boris Botvinnik , Jonathan Rosenberg

We study the vanishing cycle complex $\varphi_fA_X$ for a holomorphic function $f$ on a reduced complex analytic space $X$ with $A$ a Dedekind domain (for instance, a localization of the ring of integers of a cyclotomic field, where the…

Algebraic Geometry · Mathematics 2020-09-25 Morihiko Saito

We study versions of homological mirror symmetry for hypersurface cusp singularities and the three hypersurface simple elliptic singularities. We show that the Milnor fibres of each of these carries a distinguished Lefschetz fibration; its…

Symplectic Geometry · Mathematics 2017-05-29 Ailsa Keating

We suggest a possibility for a categorical generalization of the concept of a perverse sheaf, in which vector spaces are replaced by triangulated categories. We call such hypothetical objects perverse Schobers and consider several examples,…

Algebraic Geometry · Mathematics 2015-11-19 Mikhail Kapranov , Vadim Schechtman

If there is a topologically locally constant family of smooth algebraic varieties together with an admissible normal function on the total space, then the latter is constant on any fiber if this holds on some fiber. Combined with spreading…

Algebraic Geometry · Mathematics 2014-11-25 Morihiko Saito

In this paper we investigate the behavior of the sigma function over the family of cyclic trigonal curves $X_s$ defined by the equation $y^3 =x(x-s)(x-b_1)(x-b_2)$ in the affine $(x,y)$ plane, for $s\in D_\varepsilon:=\{s \in \mathbb{C} |…

Algebraic Geometry · Mathematics 2022-08-24 Yuri Fedorov , Jiyro Komeda , Shigeki Matsutani , Emma Previato , Kazuhiko Aomoto

In [22] Milnor proved that a real analytic map $f\colon (R^n,0) \to (R^p,0)$, where $n \geq p$, with an isolated critical point at the origin has a fibration on the tube $f|\colon B_\epsilon^n \cap f^{-1}(S_\delta^{p-1}) \to…

Algebraic Geometry · Mathematics 2021-04-12 José Luis Cisneros-Molina , Aurélio Menegon

Enhanced ind-sheaves provide a suitable framework for the irregular Riemann-Hilbert correspondence. In this paper, we give some precisions on nearby and vanishing cycles for enhanced perverse objects in dimension one. As an application, we…

Algebraic Geometry · Mathematics 2024-02-23 Andrea D'Agnolo , Masaki Kashiwara

In this paper we study the cyclicity of sliding cycles for regularized piecewise smooth visible-invisible two-folds, in the presence of singularities of the Filippov sliding vector field located away from two-folds. We obtain a slow-fast…

Dynamical Systems · Mathematics 2025-03-14 Jicai Huang , Renato Huzak , Otavio Henrique Perez , Jinhui Yao

We consider the restriction of twice differentiable functionals on a Hilbert space to families of subspaces that vary continuously with respect to the gap metric. We study bifurcation of branches of critical points along these families, and…

Functional Analysis · Mathematics 2017-02-07 Anna Maria Candela , Nils Waterstraat

We define and study new filtrations called of stratification of a perverse sheaf on a scheme; beside the cases of the weight or monodromy filtrations, these filtrations are available whatever are the ring of coefficients. We illustrate…

Algebraic Geometry · Mathematics 2015-03-12 Pascal Boyer

For analytic map germs $f: (\mathbb{R}^n, 0)\to (\mathbb{R}, 0)$ having an isolated critical value in the origin with $\dim V(f)>0$ and satisfying the transversality property of D.B. Massey we show that for $c>0$ a large enough constant,…

Algebraic Geometry · Mathematics 2021-08-17 Lars Andersen

Let Y be a hypersurface in projective space having only ordinary double points as singularities. We prove a variant of a conjecture of L. Wotzlaw on an algebraic description of the graded quotients of the Hodge filtration on the top…

Algebraic Geometry · Mathematics 2017-08-09 Alexandru Dimca , Morihiko Saito

We prove that for two germs of analytic mappings $f,g\colon (\mathbb{C}^n,0) \rightarrow (\mathbb{C}^p,0)$ with the same Newton polyhedra which are (Khovanskii) non-degenerate and their zero sets are complete intersections with isolated…

Algebraic Geometry · Mathematics 2020-06-12 Tat Thang Nguyen