scholarly journals Motivic integration and Milnor fiber

2021 ◽  
Author(s):  
Goulwen Fichou ◽  
Yimu Yin
Keyword(s):  
Motivic Integration ◽  
Milnor Fiber

scholarly journals Characteristic Cohomology I: Singularities of Given Type

2020 ◽  
Author(s):  
James Damon
Keyword(s):  
Geometric Criterion ◽  
Milnor Fiber ◽  
Compact Models ◽  
Singular Matrices

Abstract For a germ of a variety $\mathcal{V}, 0 \subset \mathbb C^N, 0$, a singularity $\mathcal{V}_0$ of ‘type $\mathcal{V}$’ is given by a germ $f_0 : \mathbb C^n, 0 \to \mathbb C^N, 0$ which is transverse to $\mathcal{V}$ in an appropriate sense so that $\mathcal{V}_0 = f_0^{\,-1}(\mathcal{V})$. If $\mathcal{V}$ is a hypersurface germ, then so is $\mathcal{V}_0 $, and by transversality ${\operatorname{codim}}_{\mathbb C} {\operatorname{sing}}(\mathcal{V}_0) = {\operatorname{codim}}_{\mathbb C} {\operatorname{sing}}(\mathcal{V})$ provided $n > {\operatorname{codim}}_{\mathbb C} {\operatorname{sing}}(\mathcal{V})$. So $\mathcal{V}_0, 0$ will exhibit singularities of $\mathcal{V}$ up to codimension n. For singularities $\mathcal{V}_0, 0$ of type $\mathcal{V}$, we introduce a method to capture the contribution of the topology of $\mathcal{V}$ to that of $\mathcal{V}_0$. It is via the ‘characteristic cohomology’ of the Milnor fiber (for $\mathcal{V}, 0$ a hypersurface), and complement and link of $\mathcal{V}_0$ (in the general case). The characteristic cohomology of the Milnor fiber $\mathcal{A}_{\mathcal{V}}(\,f_0; R)$, and respectively of the complement $\mathcal{C}_{\mathcal{V}}(\,f_0; R)$, are subalgebras of the cohomology of the Milnor fibers, respectively the complement, with coefficients R in the corresponding cohomology. For a fixed $\mathcal{V}$, they are functorial over the category of singularities of type $\mathcal{V}$. In addition, for the link of $\mathcal{V}_0$ there is a characteristic cohomology subgroup $\mathcal{B}_{\mathcal{V}}(\,f_0, \mathbf{k})$ of the cohomology of the link over a field $\mathbf{k}$ of characteristic 0. The cohomologies $\mathcal{C}_{\mathcal{V}}(\,f_0; R)$ and $\mathcal{B}_{\mathcal{V}}(\,f_0, \mathbf{k})$ are shown to be invariant under the $\mathcal{K}_{\mathcal{V}}$-equivalence of defining germs f0, and likewise $\mathcal{A}_{\mathcal{V}}(\,f_0; R)$ is shown to be invariant under the $\mathcal{K}_{H}$-equivalence of f0 for H the defining equation of $\mathcal{V}, 0$. We give a geometric criterion involving ‘vanishing compact models’ for both the Milnor fibers and complements which detect non-vanishing subalgebras of the characteristic cohomologies, and subgroups of the characteristic cohomology of the link. Also, we consider how in the hypersurface case the cohomology of the Milnor fiber is a module over the characteristic cohomology $\mathcal{A}_{\mathcal{V}}(\,f_0; R)$. We briefly consider the application of these results to a number of cases of singularities of a given type. In part II, we specialize to the case of matrix singularities and using results on the topology of the Milnor fibers, complements and links of the varieties of singular matrices obtained in another paper allow us to give precise results for the characteristic cohomology of all three types.

Motivic Integration in Josquin's "Motets"

1977 ◽  
Vol 21 (2) ◽  
pp. 264 ◽  
Author(s):  
Irving Godt ◽  
Josquin
Keyword(s):  
Motivic Integration

Motivic Integration

2018 ◽  
Author(s):  
Antoine Chambert-Loir ◽  
Johannes Nicaise ◽  
Julien Sebag
Keyword(s):  
Motivic Integration

scholarly journals On the Monodromy of Milnor Fibers of Hyperplane Arrangements

2014 ◽  
Vol 57 (4) ◽  
pp. 697-707 ◽  
Author(s):  
Pauline Bailet
Keyword(s):  
Cohomology Group ◽  
Hyperplane Arrangement ◽  
General Setting ◽  
Hyperplane Arrangements ◽  
Milnor Fiber ◽  
First Cohomology Group

AbstractWe describe a general setting where the monodromy action on the first cohomology group of the Milnor fiber of a hyperplane arrangement is the identity.

scholarly journals Tate properties, polynomial-count varieties, and monodromy of hyperplane arrangements

2012 ◽  
Vol 206 ◽  
pp. 75-97 ◽  
Author(s):  
Alexandru Dimca
Keyword(s):  
Hyperplane Arrangement ◽  
Hyperplane Arrangements ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Monodromy Operator ◽  
Low Dimensions ◽  
Milnor Fiber ◽  
Necessary And Sufficient ◽  
Complex Hyperplane

AbstractThe order of the Milnor fiber monodromy operator of a central hyperplane arrangement is shown to be combinatorially determined. In particular, a necessary and sufficient condition for the triviality of this monodromy operator is given.It is known that the complement of a complex hyperplane arrangement is cohomologically Tate and, if the arrangement is defined over ℚ, has polynomial count. We show that these properties hold for the corresponding Milnor fibers if the monodromy is trivial.We construct a hyperplane arrangement defined over ℚ, whose Milnor fiber has a nontrivial monodromy operator, is cohomologically Tate, and has no polynomial count. Such examples are shown not to exist in low dimensions.

scholarly journals A computational approach to Milnor fiber cohomology

2017 ◽  
Vol 29 (4) ◽  
Author(s):  
Alexandru Dimca ◽  
Gabriel Sticlaru
Keyword(s):  
Computational Approach ◽  
Milnor Fiber

AbstractIn this paper we consider the Milnor fiber

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