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We study minimal surfaces in generic sub-Riemannian manifolds with sub-Riemannian structures of co-rank one. These surfaces can be defined as the critical points of the so-called {\it horizontal} area functional associated to the canonical…

Analysis of PDEs · Mathematics 2007-09-20 Nataliya Shcherbakova

We generalize Milnor link invariants to all types of surface-links in $4$--space (possibly with boundary). This is achieved by using the notion of cut-diagram, which is a 2-dimensional generalization of Gauss diagrams, associated to…

Geometric Topology · Mathematics 2025-12-02 Benjamin Audoux , Jean-Baptiste Meilhan , Akira Yasuhara

Milnor's $\bar{\mu}$-invariants of links in the $3$-sphere $S^3$ vanish on any link concordant to a boundary link. In particular, they are trivial on any knot in $S^3$. Here we consider knots in thickened surfaces $\Sigma \times [0,1]$,…

Geometric Topology · Mathematics 2022-11-02 Micah Chrisman

We consider knotted annuli in 4-space, called 2-string-links, which are knotted surfaces in codimension two that are naturally related, via closure operations, to both 2-links and 2-torus links. We classify 2-string-links up to…

Geometric Topology · Mathematics 2017-12-05 Benjamin Audoux , Jean-Baptiste Meilhan , Emmanuel Wagner

We exhibit an encoding of knots into processes in the {\pi}-calculus such that knots are ambient isotopic if and only their encodings are weakly bisimilar.

Geometric Topology · Mathematics 2010-09-20 L. G. Meredith , David F. Snyder

We describe a natural decomposition of a normal complex surface singularity $(X,0)$ into its "thick" and "thin" parts. The former is essentially metrically conical, while the latter shrinks rapidly in thickness as it approaches the origin.…

Algebraic Geometry · Mathematics 2014-07-29 Lev Birbrair , Walter D Neumann , Anne Pichon

Smooth cubic fourfolds are linked to K3 surfaces via their Hodge structures, due to work of Hassett, and via Kuznetsov's K3 category A. The relation between these two viewpoints has recently been elucidated by Addington and Thomas. In this…

Algebraic Geometry · Mathematics 2019-02-20 Daniel Huybrechts

A link is called $\chi-$slice if it bounds a smooth properly embedded surface in the 4-ball with no closed components and Euler characteristic 1. If a link has a single component, then it is $\chi-$slice if and only if it is slice. One…

Geometric Topology · Mathematics 2023-06-05 Sophia Fanelle , Evan Huang , Ben Huenemann , Weizhe Shen , Jonathan Simone , Hannah Turner

Knots naturally appear in continuous dynamical systems as flow periodic trajectories. However, discrete dynamical systems are also closely connected with the theory of knots and links. For example, for Pixton diffeomorphisms, the…

Dynamical Systems · Mathematics 2023-03-09 Valeriy Bardakov , Tatyana Kozlovskaya , Olga Pochinka

The linking number $lk$ is defined if link components are zero homologous. Our affine linking invariant $alk$ generalizes $lk$ to the case of linked submanifolds with arbitrary homology classes. We apply $alk$ to the study of causality in…

Geometric Topology · Mathematics 2008-11-26 Vladimir Chernov , Yuli B. Rudyak

The main result of the paper states that a connected complex affine algebraic curve is Lipschitz normally embedded (shortened to LNE afterwards) in $\mathbb{C}^n$ if and only if its germ at any singular point is a finite union of…

Algebraic Geometry · Mathematics 2023-11-28 André Costa , Vincent Grandjean , Maria Michalska

In this paper we investigate the 0-concordance classes of 2-knots in $S^4$, an equivalence relation that is related to understanding smooth structures on 4-manifolds. Using Rochlin's invariant, and invariants arising from Heegaard-Floer…

Geometric Topology · Mathematics 2019-07-16 Nathan Sunukjian

We show that any two same-genus, oriented, boundary parallel surfaces bounded by a non-split, alternating link into the 4-ball are smoothly isotopic fixing boundary. In other words, any same-genus Seifert surfaces for a non-split,…

Geometric Topology · Mathematics 2026-01-14 Seungwon Kim , Maggie Miller , Jaehoon Yoo

We establish inequalities that constrain the genera of smooth cobordisms between knots in 4-dimensional cobordisms. These "relative adjunction inequalities" improve the adjunction inequalities for closed surfaces which have been…

Geometric Topology · Mathematics 2021-08-10 Matthew Hedden , Katherine Raoux

Given a geodesic inside a simply-connected, complete, non-positively curved Riemannian (NPCR) manifold M, we get an associated geodesic inside the asymptotic cone Cone(M). Under mild hypotheses, we show that if the latter is contained…

Differential Geometry · Mathematics 2008-01-24 S. Francaviglia , J. -F. Lafont

We construct the equivariant analytic lattice cohomology associated with the analytic type of a complex normal surface singularity whenever the link is a rational homology sphere. It is the categorification of the equivariant geometric…

Algebraic Geometry · Mathematics 2021-08-31 Tamás Ágoston , András Némethi

Let M be $S^3$, $S^1\times S^2$, or a lens space L(p,q), and let k be a (1,1)-knot in M, i.e., a knot which is of 1-bridge with respect to a Heegaard torus. We show that if there is a closed meridionally incompressible surface in the…

Geometric Topology · Mathematics 2009-09-29 Mario Eudave-Munoz

We use topological methods to study various semicontinuity properties of spectra of singular points of plane algebraic curves and of polynomials in two variables at infinity. Using Seifert forms and the Tristram--Levine signatures of links,…

Geometric Topology · Mathematics 2014-02-26 Maciej Borodzik , Andras Nemethi

We prove that finite area isolated singularities of surfaces with constant positive curvature in R^3 are removable singularities, branch points or immersed conical singularities. We describe the space of immersed conical singularities of…

Differential Geometry · Mathematics 2010-07-16 Jose A. Galvez , Laurent Hauswirth , Pablo Mira

In this paper, we define grid homologies for singular links in lens spaces and use them to construct a resolution cube for knot Floer homology of regular links in lens spaces. The results will first be proved over $\mathbb{Z}/2\mathbb{Z}$…

Geometric Topology · Mathematics 2025-03-28 Yonghan Xiao