arXiv research

New twisted versions of wild character varieties created.

The article examines twisted cohomologies on algebraic and analytic varieties.

Stratifies representation varieties of twisted Hopf links.

The authors study in detail new types of varieties with degenerate Gauss maps: varieties with multiple foci and their particular case, the so-called twisted cones. They prove an existence theorem for twisted cones and describe their structure.

Study representation varieties of twisted Hopf links using combinatorial and Hodge theory.

The paper describes invariant twisted Kähler-Einstein metrics on flag varieties.

Study of twisted $L^2$-torsion on 3-manifold character varieties.

Character variety of Borromean link solved, Alexander polynomial formula found.

Formula for twisted Alexander polynomials of torus links.

Given a 3 manifold M with torus boundary and an ideal triangulation, Yoshida and Tillmann give different methods to construct surfaces embedded in M from ideal points of the deformation variety. Yoshida builds a surface from twisted squares whereas Tillmann produces a spun-normal surface. We investigate the relation be…

The paper proves a vanishing identity for twist knots using character varieties.

Study character variety of a special 3-manifold, finding a polynomial formula.

We study the twisted Alexander polynomial from the viewpoint of the SL(2,C)-character variety of nonabelian representations of a knot group. It is known that if a knot is fibered, then the twisted Alexander polynomials associated with nonabelian SL(2,C)-representations are all monic. In this paper, we show that the con…

The paper shows how to destabilize unstable Fano varieties using stability thresholds.

The study examines dynamics on SU(2)-representation varieties for surfaces and non-orientable surfaces.

The paper certifies projective rigidity for once-punctured torus bundles using twisted Alexander polynomials.

Formulae for volumes and A-polynomials of a specific link.

We introduce a new approach for computing the monodromy of the Hitchin map and use this to completely determine the monodromy for the moduli spaces of $L$-twisted $G$-Higgs bundles, for the groups $G = GL(2,\mathbb{C})$, $SL(2,\mathbb{C})$ and $PSL(2,\mathbb{C})$. We also determine the twisted Chern class of the regula…

In this paper we prove that if $M_K$ is the complement of a non-fibered twist knot $K$ in $\mathbb S^3$, then $M_K$ is not commensurable to a fibered knot complement in a $\mathbb Z/ 2 \mathbb Z$-homology sphere. To prove this result we derive a recursive description of the character variety of twist knots and then pro…

Researchers describe character varieties for Hopf links, proving geometric properties.

New recurrence formula for stable twisted Betti numbers of configuration spaces and spaces of maximal tori.

In this paper we consider some families of links, including (-2,2m+1,2n)-pretzel links and twisted Whitehead links. We calculate the character varieties of these families, and determine the number of irreducible components of these character varieties.

For a fibered knot in the 3-sphere the twisted Alexander polynomial associated to an SL(2,C)-character is known to be monic. It is conjectured that for a nonfibered knot there is a curve component of the SL(2,C)-character variety containing only finitely many characters whose twisted Alexander polynomials are monic, i.…

Let $X$ be a smooth projective variety over $\mathbb C$. We prove that a twisted Higgs vector bundle $(\calE\, ,θ)$ on $X$ admits an Einstein--Hermitian connection if and only if $(\calE\, ,θ)$ is polystable. A similar result for twisted vector bundles (no Higgs fields) was proved by S. Wang in \cite{Wa}. Our approach …

We introduce a norm on the space of test configurations, which we call the minimum norm. We conjecture that uniform K-stability with respect to this norm is equivalent to the existence of a constant scalar curvature Kähler metric. This notion of uniform K-stability is analogous to coercivity of the Mabuchi functional. …

We observe the twisted Alexander polynomial for metabelian representations of knot groups into SL(2,C) and study relations to the characterizations of metabelian representations in the character varieties. We give a factorization of the twisted Alexander polynomial for irreducible metabelian representations with the ad…

We show that all twist knots, certain double twist knots and some other 2-bridge knots are minimal elements for the partial ordering on the set of prime knots. The key to these results are presentations of their character varieties using Chebyshev polynomials and a criterion for irreducibility of a polynomial of two va…

Link homology compared with geometric link invariants using Bott-Samelson varieties.

New method for moduli spaces of twisted quiver representations and Higgs bundles.

We compute both natural and smooth models for the $SL_2(\mathbb C)$ character varieties of the two component double twist links, an infinite family of two-bridge links indexed as $J(k,l)$. For each $J(k,l)$, the component(s) of the character variety containing characters of irreducible representations are birational to…

Simplified A-polynomial calculation for twisted knots.

Legendrian products can be twist spuns under certain conditions.

The paper studies flow lines on Higgs bundle moduli spaces, classifying them via secant varieties.

The main goal of the present paper is the construction of twisted generalized differential cohomology theories and the comprehensive statement of its basic functorial properties. Technically it combines the homotopy theoretic approach to (untwisted) generalized differential cohomology developed by Hopkins-Singer and la…

New proof shows coherent sheaves quasi-equivalent to constructible sheaves on torus.

The paper derives formulas for symplectic volume forms on surface representation varieties.

We give an extension of Fox's formula of the Alexander polynomial for double branched covers over the three-sphere. Our formula provides the Reidemeister torsion of a double branched cover along a knot for a non-trivial one dimensional representation by the product of two factors derived from the knot group. One of the…

The paper proves positivity of a $L^2$-torsion function for certain 3-manifolds.

Study measures invariant DH on twisted moduli spaces.

Existence of Kähler-Ricci solitons on smoothable Q-Fano varieties proven.

We study incompressible surfaces constructed by Culler-Shalen theory in the context of twisted Alexander polynomials. For a $1$st cohomology class of a $3$-manifold the coefficients of twisted Alexander polynomials induce regular functions on the $SL_2(\mathbb{C})$-character variety. We prove that if an ideal point giv…

Let $G$ be a linear connected complex reductive Lie group. The purpose of this paper is to give explicit symplectic isomorphisms from twisted cotangent bundles of the complex generalized flag varieties, whose transition functions are given by affine transformations instead of linear transformations, onto the complex co…

Obstruction theory for complex bigraded differential algebras.

Exotic diffeomorphisms found on complex surfaces and 4-manifolds.

Study tangle invariants using pillowcase Fukaya category and character varieties.

Let M be a twisted interval bundle over a nonorientable hyperbolizable surface. Let X(M) be the PSL(2,C)-character variety of π_1(M). We examine the dynamics of the action of Out(π_1(M)) on X(M), and in particular, we find an open set on which the action is properly discontinuous that is strictly larger than the interi…

Site-specific recombination on supercoiled circular DNA molecules can yield a variety of knots and catenanes. Twist knots are some of the most common conformations of these products and they can act as substrates for further rounds of site-specific recombination. They are also one of the simplest families of knots and …

The coefficients of twisted Alexander polynomials of a knot induce regular functions of the $SL_2(\mathbb{C})$-character variety. We prove that the function of the highest degree has a finite value at an ideal point which gives a minimal genus Seifert surface by Culler-Shalen theory. It implies a partial affirmative an…