arXiv research

We explain how the generalized Milnor-Wood inequality for reductive representations of a cocompact complex-hyperbolic lattice into a Hermitian Lie group translates, under the non-abelian Hodge correspondence, into various kinds of Milnor-Wood inequalities for Higgs bundles. This clarifies the relation between the repre…

Study of Fukaya-Seidel categories for surface Lefschetz fibrations.

We prove a Milnor-Wood inequality for representations of the fundamental group of a compact complex hyperbolic manifold in the group of isometries of quaternionic hyperbolic space. Of special interest is the case of equality, and its application to rigidity. We show that equality can only be achieved for totally geodes…

New volume invariant for cocycles of hyperbolic lattices, proving rigidity results.

Let $\mathcal{A}$ be a central hyperplane arrangement in $\mathbb{C}^{n+1}$ and $H_i,i=1,2,...,d$ be the defining equations of the hyperplanes of $\mathcal{A}$. Let $f=\prod_i H_i$. There is a global Milnor fibration $F\hookrightarrow \mathbb{C}^{n+1} \setminus \mathcal{A} \xrightarrow{f} \mathbb{C}^*,$ where $F$ is ca…

New findings on isospectral tori and harmonic maps between flat tori.

We encode the variation structure of a quasihomogeneous polynomial with an isolated singularity as introduced by Nemethi in a set of spectral flows of the signature operator on the Milnor bundle by varying global elliptic boundary conditions in a specific way using the quasihomogeneous circle action on the Brieskorn la…

We consider the problem of existence of representations of topological groupoids on a principal bundle and the classification of such representations up to gauge transformation. Such representations naturally occur in various contexts such as gauge theory, lattice gauge fields, equivariant bundles, etc. In the course o…

We study the secondary structure of RNA determined by Watson-Crick pairing without pseudo-knots using Milnor invariants of links. We focus on the first non-trivial invariant, which we call the Heisenberg invariant. The Heisenberg invariant, which is an integer, can be interpreted in terms of the Heisenberg group as wel…

Maximal representations in exceptional Hermitian Lie groups classified for complex hyperbolic lattices.

We propose a definition of the Toledo invariant for representations of fundamental groups of smooth varieties of general type into semisimple Lie groups of Hermitian type. This definition allows to generalize the results known in the classical case of representations of complex hyperbolic lattices to this new setting: …

Planar multilinks prove rational singularities in surface geometry.

Let G be either SU(p,2) with p>=2, Sp(2,R) or SO(p,2) with p>=3. The symmetric spaces associated to these G's are the classical bounded symmetric domains of rank 2, with the exceptions of SO*(8)/U(4) and SO*(10)/U(5). Using the correspondence between representations of fundamental groups of Kähler manifolds and Higgs b…

Study symplectic fillings of lens spaces, focusing on virtually overtwisted contact structures.

Study Milnor invariants for covering links to distinguish certain links.

Study Stein and Milnor fillings of links from surface singularities.

Several proofs of Fáry--Milnor theorem are presented.

In analogy with the holomorphic case, we compare the topology of Milnor fibrations associated to a meromorphic germ f/g : the local Milnor fibrations given on Milnor tubes over punctured discs around the critical values of f/g, and the Milnor fibration on a sphere.

Combines combinatorial method to extend Milnor invariants to welded links.

Reconfigures Milnor invariants using unipotent Magnus embeddings.

Study new invariants for string links using Milnor and Morita-Milnor homomorphisms.

Given a clover link, we construct a bottom tangle by using a disk/band surface of the clover link. Since the Milnor number is already defined for a bottom tangle, we define the Milnor number for the clover link to be the Milnor number for the bottom tangle and show that for a clover link, if Milnor numbers of length k …

Higher-dimensional Milnor frames are characterized and contrasted with 3D Heisenberg and 4D nilpotent Lie algebras.

Defines linking number and Milnor invariants, their properties.

Extends Milnor's invariants to knots and links in 3-manifolds.

We describe Milnor open books and Legendrian surgery diagrams for canonical contact structures of links of some rational surface singularities. We also describe an infinite family of Milnor fillable contact 3-manifolds so that the Milnor genus (resp. Milnor norm) is strictly greater than the support genus (resp. suppor…

The study finds conditions for a special vector field in singularities.

New stability result for Milnor fibers of pure braid groups.

Explains Milnor invariants for links and surfaces.

Study the topology of Milnor boundaries for real analytic map germs.

Extends Milnor's criterion to biharmonic functions.

Extends Milnor's invariants to 3-manifolds, solving an open problem.

Fox-Milnor theorem extended to knots in thickened surfaces.

New combinatorial model for Milnor fibration using oriented matroids.

Proof of Milnor conjecture in 3 dimensions using limit spaces.

Defines Milnor number for foliations and shows its topological invariance.

Paper introduces simplified formulas for Milnor's triple linking number.

Milnor fibrations have been studied since 1960's. In this paper, we study singular points of differentiable maps, called Milnor fibration product maps, obtained by several Milnor fibrations. We give a characterization of singular points of such product maps, and for the case of certain weighted homogeneous polynomials,…

We give formulas expressing Milnor invariants of an n-component link L in the 3-sphere in terms of the HOMFLYPT polynomial as follows. If the Milnor invariant \barμ_J(L) vanishes for any sequence J with length at most k, then any Milnor \barμ-invariant \barμ_I(L) with length between 3 and 2k+1 can be represented as a c…

This paper characterizes Milnor invariants using diagrammatic methods.

Study of first homology group of Milnor fiber boundary for generic hyperplane arrangements in C^3.

For an $n$-component link $L$, the Milnor's isotopy invariant is defined for each multi-index $I=i_1i_2...i_m (i_j\in\n)$. Here $m$ is called the length. Let $r(I)$ denote the maximam number of times that any index appears. It is known that Milnor invariants with $r=1$ are link-homotopy invariant. N. Habegger and X. S.…

Proves non-solvability of concordance groups using Milnor invariants.

Study volume growth in Milnor fibers using real Lagrangians.

New method normalizes Milnor fibrations for real analytic maps.

New method determines arrangement combinatorics from Milnor fiber boundary.

Floer homology linked to Milnor fibers for certain singularities.

Formula calculates homology groups of Milnor fibres for real hypersurface singularities.