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We obtain an exact formula for the probability that a uniformly random spanning tree of the $2$-by-$n$ square grid is ``balanced'' in the sense that it has an edge whose removal partitions its vertices into two sets of equal size. We…

Combinatorics · Mathematics 2025-12-18 Makenzie Gallagher , Kristopher Tapp

The only knots that are tunnel number one and genus one are those that are already known: 2-bridge knots obtained by plumbing together two unknotted annuli and the satellite examples classified by Eudave-Munoz and by Morimoto-Sakuma. This…

Geometric Topology · Mathematics 2007-05-23 Martin Scharlemann

The nonorientable four-ball genus of a knot $K$ in $S^3$ is the minimal first Betti number of nonorientable surfaces in $B^4$ bounded by $K$. By amalgamating ideas from involutive knot Floer homology and unoriented knot Floer homology, we…

Geometric Topology · Mathematics 2025-09-22 Fraser Binns , Sungkyung Kang , Jonathan Simone , Paula Truöl

We define a filtration of the smooth concordance group based on the genus of representative knots. We use the Heegaard Floer epsilon and Upsilon invariants to prove the quotient groups with respect to this filtration are infinitely…

Geometric Topology · Mathematics 2016-11-30 Shida Wang

We show that two-bridge knots and alternating fibered knots admit no purely cosmetic surgeries, i.e., no pair of distinct Dehn surgeries on such a knot produce 3-manifolds that are homeomorphic as oriented manifolds. Our argument, based on…

Geometric Topology · Mathematics 2021-11-10 Kazuhiro Ichihara , In Dae Jong , Thomas W. Mattman , Toshio Saito

Negami found an upper bound on the stick number $s(K)$ of a nontrivial knot $K$ in terms of the minimal crossing number $c(K)$ of the knot which is $s(K) \leq 2 c(K)$. Furthermore McCabe proved $s(K) \leq c(K) + 3$ for a $2$-bridge knot or…

Geometric Topology · Mathematics 2014-11-10 Youngsik Huh , Sungjong No , Seungsang Oh

We define the {\it Wirtinger number} of a link, an invariant closely related to the meridional rank. The Wirtinger number is the minimum number of generators of the fundamental group of the link complement over all meridional presentations…

Geometric Topology · Mathematics 2020-08-17 Ryan Blair , Alexandra Kjuchukova , Roman Velazquez , Paul Villanueva

In this paper we use continued fractions to study a partial order on the set of 2-bridge knots derived from the work of Ohtsuki, Riley, and Sakuma. We establish necessary and sufficient conditions for any set of 2-bridge knots to have an…

Geometric Topology · Mathematics 2011-01-24 Scott M. Garrabrant , Jim Hoste , Patrick D. Shanahan

The structure of the first homology group of a cyclic covering of a knot is an important invariant well known in the knot theory. In the last century, H. Seifert developed a general approach to compute the homology group of the covering.…

Combinatorics · Mathematics 2021-11-09 Ilya Mednykh

We prove that the detection rate of n-crossing alternating links by many standard link invariants decays exponentially in n, implying that they detect alternating links with probability zero. This phenomenon applies broadly, in particular…

Geometric Topology · Mathematics 2025-12-02 Tuomas Kelomäki , Abel Lacabanne , Daniel Tubbenhauer , Pedro Vaz , Victor L. Zhang

We give a geometric proof of the following result of Juhasz. \emph{Let $a_g$ be the leading coefficient of the Alexander polynomial of an alternating knot $K$. If $|a_g|<4$ then $K$ has a unique minimal genus Seifert surface.} In doing so,…

Geometric Topology · Mathematics 2018-07-17 Jessica E. Banks

Fox conjectured the Alexander polynomial of an alternating knot is trapezoidal, i.e. the coefficients first increase, then stabilize and finally decrease in a symmetric way. Recently, Hirasawa and Murasugi further conjectured a relation…

Geometric Topology · Mathematics 2018-01-12 Wenzhao Chen

The twisted torus knots lie on the standard genus 2 Heegaard surface for $S^3$, as do the primitive/primitive and primitive/Seifert knots. It is known that primitive/primitive knots are fibered, and that not all primitive/Seifert knots are…

Geometric Topology · Mathematics 2015-05-21 Brandy Guntel Doleshal

Given a band sum of a split two-component link along a nontrivial band, we obtain a family of knots indexed by the integers by adding any number of full twists to the band. We show that the knots in this family have the same Heegaard knot…

Geometric Topology · Mathematics 2023-02-01 Joshua Wang

We call a knot in the 3-sphere $SU(2)$-simple if all representations of the fundamental group of its complement which map a meridian to a trace-free element in $SU(2)$ are binary dihedral. This is a generalisation of being a 2-bridge knot.…

Geometric Topology · Mathematics 2017-02-15 Raphael Zentner

Given any closed, connected, orientable $3$--manifold and integers $g\geq g(M), D > 0$, we show the existence of knots in $M$ whose genus $g$ bridge number is greater than $D$. These knots lie in a page of an open book decomposition of $M$,…

Geometric Topology · Mathematics 2015-02-17 R. Sean Bowman , Jesse Johnson

We study 2-string free tangle decompositions of knots with tunnel number two. As an application, we construct infinitely many counter-examples to a conjecture in the literature stating that the tunnel number of the connected sum of prime…

Geometric Topology · Mathematics 2013-06-18 João Miguel Nogueira

We provide a new bound on the maximum degree of the Jones polynomial of a positive link with second Jones coefficient equal to $\pm 1$ or $\pm 2$. This builds upon the result of our previous work, in which we found such a bound for positive…

Geometric Topology · Mathematics 2023-03-24 Lizzie Buchanan

We introduce an unknotting-type number of knot projections that gives an upper bound of the crosscap number of knots. We determine the set of knot projections with the unknotting-type number at most two, and this result implies classical…

Geometric Topology · Mathematics 2020-08-26 Noboru Ito , Yusuke Takimura

It has been conjectured that for knots $K$ and $K'$ in $S^3$, $w(K#K')= w(K)+w(K')-2$. Scharlemann and Thompson have proposed potential counterexamples to this conjecture. For every $n$, they proposed a family of knots ${K^n_i}$ for which…

Geometric Topology · Mathematics 2009-08-31 Ryan Blair , Maggy Tomova
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