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It is known that every exotic smooth structure on a simply connected closed 4-manifold is determined by a codimention zero compact contractible Stein submanifold and an involution on its boundary. Such a pair is called a cork. In this…

Geometric Topology · Mathematics 2014-02-26 Selman Akbulut , Kouichi Yasui

We present new computations of approximately length-minimizing polygons with fixed thickness. These curves model the centerlines of "tight" knotted tubes with minimal length and fixed circular cross-section. Our curves approximately…

Differential Geometry · Mathematics 2010-02-10 Ted Ashton , Jason Cantarella , Michael Piatek , Eric Rawdon

Weaving knots are alternating knots with the same projection as torus knots, and were conjectured by X.-S. Lin to be among the maximum volume knots for fixed crossing number. We provide the first asymptotically correct volume bounds for…

Geometric Topology · Mathematics 2016-12-21 Abhijit Champanerkar , Ilya Kofman , Jessica S. Purcell

In this paper, we study how to fold a specified origami crease pattern in order to minimize the impact of paper thickness. Specifically, origami designs are often expressed by a mountain-valley pattern (plane graph of creases with relative…

Data Structures and Algorithms · Computer Science 2016-03-22 Erik D. Demaine , David Eppstein , Adam Hesterberg , Hiro Ito , Anna Lubiw , Ryuhei Uehara , Yushi Uno

Knot concordance plays a crucial role in the low dimensional topology. We propose a very elementary techniques which allows one to construct a lot of sliceness obstructions for knots in the full torus. Our approach deals with group…

Geometric Topology · Mathematics 2022-03-22 Vassily Olegovich Manturov , Igor Mikhailovich Nikonov

The topological framework of circuit topology has recently been introduced to complement knot theory and to help in understanding the physics of molecular folding. Naturally evolved linear molecular chains, such as proteins and nucleic…

Geometric Topology · Mathematics 2021-09-07 Alireza Mashaghi , Roland van der Veen

A foundational result in origami mathematics is Kawasaki and Justin's simple, efficient characterization of flat foldability for unassigned single-vertex crease patterns (where each crease can fold mountain or valley) on flat material. This…

Computational Geometry · Computer Science 2022-04-11 Lily Chung , Erik D. Demaine , Dylan Hendrickson , Victor Luo

We construct new knot polynomials. Let $V$ be the standard solid torus in 3-space and let $pr$ be its standard projection onto an annulus. Let $M$ be the space of all smooth oriented knots in $V$ such that the restriction of $pr$ is an…

Geometric Topology · Mathematics 2007-05-23 Thomas Fiedler

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

In the present paper, we address the problem how to get a map from knots in the cylinder and on the thickened torus to some (generalisation of) virtual knots called virtual-flat knots. The main construction takes a diagram on a cylinder…

Geometric Topology · Mathematics 2022-10-19 V. O. Manturov , I. M. Nikonov

In 2003, Ozsv\'ath, Szab\'o, and Rasmussen introduced the $\tau$ invariant for knots, and in 2011, Sarkar published a computational shortcut for the $\tau$ invariant of knots that can be represented by diagonal grid diagrams. Previously,…

Geometric Topology · Mathematics 2025-09-10 Jackson Arndt , Malia Jansen , Payton McBurney , Katherine Vance

Knots are commonly represented and manipulated via diagrams, which are decorated planar graphs. When such a knot diagram has low treewidth, parameterized graph algorithms can be leveraged to ensure the fast computation of many invariants…

Computational Geometry · Computer Science 2023-03-16 Corentin Lunel , Arnaud de Mesmay

We study smooth, proper embeddings of noncompact surfaces in 4-manifolds, focusing on exotic planes and annuli, i.e., embeddings pairwise homeomorphic to the standard embeddings of R^2 and R^2-int D^2 in R^4. We encounter two uncountable…

Geometric Topology · Mathematics 2025-01-08 Robert E. Gompf

This paper is expository and is accessible to students. We define simple invariants of knots or links (linking number, Arf-Casson invariants and Alexander-Conway polynomials) motivated by interesting results whose statements are accessible…

Geometric Topology · Mathematics 2021-12-15 A. Skopenkov

We present a conjecture for the power-law exponent in the asymptotic number of types of plane curves as the number of self-intersections goes to infinity. In view of the description of prime alternating links as flype equivalence classes of…

Mathematical Physics · Physics 2007-05-23 Gilles Schaeffer , Paul Zinn-Justin

Consider a continuous flow in $\mathbb{R}^3$ or any orientable $3$-manifold. Let $(Q_1, Q_0)$ be an index pair in the sense of Conley and consider the region $N := \overline{Q_1 - Q_0}$. (An example of this is a compact $3$-manifold $N$…

Dynamical Systems · Mathematics 2024-03-28 J. J. Sánchez-Gabites

We define homotopy-theoretic invariants of knots in prime 3-manifolds. Fix a knot J in a prime 3-manifold M. Call a knot K in M concordant to J if it cobounds a properly embedded annulus with J in MxI, and call K J-characteristic if there…

Geometric Topology · Mathematics 2011-11-01 Prudence Heck

We describe an action of the concordance group of knots in the three-sphere on concordances of knots in arbitrary 3-manifolds. As an application we define the notion of almost-concordance between knots. After some basic results, we prove…

Geometric Topology · Mathematics 2018-03-07 Daniele Celoria

A special class of braids, called woven, is introduced and it is shown that every conjugation class of the braid group contains woven braids. In consequence, links can be presented as plats or closures of woven braids. Restricting on knots,…

q-alg · Mathematics 2008-02-03 Jan A. Kneissler

We give necessary conditions of a surface-knot to be ribbon concordant to another, by introducing a new variant of the cocycle invariant of surface-knots in addition to using the invariant already known. We demonstrate that twist-spins of…

Geometric Topology · Mathematics 2007-05-23 J. Scott Carter , Masahico Saito , Shin Satoh
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