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Ilia Zharkov

Publications and source records attributed to Ilia Zharkov.

17 recordsLinked to original sources
arXiv2021

Tailoring a pair of pants

We show how to deform the map $\operatorname{Log}\colon (\mathbb{C}^*)^n \to \mathbb{R}^n$ such that the image of the complex pair of pants $P^\circ \subset {(\mathbb{C}^*)^n}$ is the tropical hyperplane by showing an (ambient) isotopy between $P^\circ \subset {(\mathbb{C}^*)^n}$ and a natural polyhedral subcomplex of the product of the two skeleta $S\times Σ\subset \mathcal{A} \times \mathcal{C}$ of the amoeba $\mathcal{A}$ and the coamoeba $\mathcal{C}$ of $P^\circ$. This lays the groundwork for having the discriminant to be of codimension 2 in topological Strominger-Yau-Zaslow torus fibrations.

math.AG↗
arXiv2020

Tropical Homology

Given a tropical variety X and two non-negative integers p and q we define homology group $H_{p,q}(X)$. We show that if X is a smooth tropical variety that can be represented as the tropical limit of a 1-parameter family of complex projective varieties, then $\dim H_{p,q}(X)$ coincides with the Hodge number $h^{p,q}$ of a general member of the family.

math.AG↗
arXiv2020

Tailoring a pair of pants: the phase tropical version

We show that the phase tropical pair-of-pants is (ambient) isotopic to the complex pair-of-pants. This paper can serve as an addendum to the author's joint paper with Ruddat arXiv:2001.08267 where an isotopy between complex and ober-tropical pairs-of-pants was shown. Thus all three versions are isotopic.

math.AG↗
arXiv2017

Phase tropical hypersurfaces

We prove that a generic smooth complex hypersurface in the complex torus is homeomorphic to the corresponding phase tropical hypersurface.

math.AG↗
arXiv2013

The Orlik-Solomon Algebra and the Bergman Fan of a Matroid

Given a matroid $M$ one can define its Orlik-Solomon algebra $OS(M)$ and the Bergman fan $Σ_0(M)$. On the other hand to any rational polyhedral fan $Σ$ one can associate its tropical homology and cohomology groups $\F_\bullet(Σ)$, $\F^\bullet (Σ)$. We will show that the projective Orlik-Solomon algebra $OS_0(M)$ is canonically isomorphic to $\F^\bullet (Σ_0(M))$.

math.AG↗
arXiv2013

Tropical eigenwave and intermediate Jacobians

Tropical manifolds are polyhedral complexes enhanced with certain kind of affine structure. This structure manifests itself through a particular cohomology class which we call the eigenwave of a tropical manifold. Other wave classes of similar type are responsible for deformations of the tropical structure. If a tropical manifold is approximable by a 1-parametric family of complex manifolds then the eigenwave records the monodromy of the family around the tropical limit. With the help of tropical homology and the eigenwave we define tropical intermediate Jacobians which can be viewed as tropical analogs of classical intermediate Jacobians.

math.AG↗
arXiv2009

Tropical theta characteristics

This note is a follow up of math.AG/0612267v2 and it is largely inspired by a beautiful description of Baker-Norine of non-effective degree (g-1) divisors via chip-firing game. We consider the set of all theta characteristics on a tropical curve and identify the Riemann constant as a unique non-effective one among them.

math.AG↗
arXiv2007

Tropical curves, their Jacobians and Theta functions

We study Jacobian varieties for tropical curves. These are real tori equipped with integral affine structure and symmetric bilinear form. We define tropical counterpart of the theta function and establish tropical versions of the Abel-Jacobi, Riemann-Roch and Riemann theta divisor theorems.

math.AG↗
arXiv2004

Limiting behavior of local Calabi-Yau metrics

We use a generalization of the Gibbons-Hawking ansatz to study the behavior of certain non-compact Calabi-Yau manifolds in the large complex structure limit. This analysis provides an intermediate step toward proving the metric collapse conjecture for toric hypersurfaces and complete intersections.

math.DG↗
arXiv2003

Theta-functions for indefinite polarizations

We propose a generalization of the classical theta function to higher cohomology of the polarization line bundle on a family of complex tori with positive index. The constructed cocycles vary horizontally with respect to the (projective) flat connection on this family coming from a heat operator. They also possess modular properties similar to the classical ones.

math.AG↗
arXiv2002

Integral affine structures on spheres and torus fibrations of Calabi-Yau toric hypersurfaces I

We describe in purely combinatorial terms dual pairs of integral affine structures on spheres which come from the conjectural metric collapse of mirror families of Calabi-Yau toric hypersurfaces. The same structures arise on the base of a special Lagrangian torus fibration in the Strominger-Yau-Zaslow conjecture. We study the topological torus fibration in the large complex structure limit and show that it coincides with our combinatorial model.

math.AG↗
arXiv1998

Torus Fibrations of Calabi-Yau Hypersurfaces in Toric Varieties and Mirror Symmetry

We consider regular Calabi-Yau hypersurfaces in $N$-dimensional smooth toric varieties. On such a hypersurface in the neighborhood of the large complex structure limit point we construct a fibration over a sphere $S^{N-1}$ whose generic fibers are tori $T^{N-1}$. Also for certain one-parameter families of such hypersurfaces we show that the monodromy transformation is induced by a translation of the $T^{N-1}$ fibration by a section. Finally we construct a dual fibration and provide some evidence that it describes the mirror family.

math.AG↗