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Related papers: Splicing and the SL(2,C) Casson invariant

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We show that the integer homology sphere obtained by splicing two nontrivial knot complements in integer homology sphere L-spaces has Heegaard Floer homology rank strictly greater than one. In particular, splicing the complements of…

Geometric Topology · Mathematics 2015-09-11 Matthew Hedden , Adam Simon Levine

We give a precise description of splicing formulas from a previous paper in terms of knot Floer complex associated with a knot in homology sphere.

Geometric Topology · Mathematics 2008-04-09 Eaman Eftekhary

An attempt is made to conceptualize the derivation as well as to facilitate the computation of Ohtsuki's rational invariants $\lambda_n$ of integral homology 3-spheres extracted from Reshetikhin-Turaev SU(2) quantum invariants. Several…

q-alg · Mathematics 2008-02-03 Xiao-Song Lin , Zhenghan Wang

Using elementary counting methods of weight systems for finite type invariants of knots and integral homology 3-spheres, in the spirit of [B-NG], we answer positively three questions raised in [Ga]. In particular, we exhibit a one-to-one…

q-alg · Mathematics 2016-09-08 S. Garoufalidis

Recently, Mullins calculated the Casson-Walker invariant of the 2-fold cyclic branched cover of an oriented link in S^3 in terms of its Jones polynomial and its signature, under the assumption that the 2-fold branched cover is a rational…

Geometric Topology · Mathematics 2007-05-23 Stavros Garoufalidis

Gauss diagram formulas are extensively used to study Vassiliev link invariants. Now we apply this approach to invariants of 3-manifolds, considering manifolds given by surgery on framed links in the 3-sphere. We study the lowest degree case…

Geometric Topology · Mathematics 2011-08-23 Sergei Matveev , Michael Polyak

Updated rerefences and introduction. Given a knot in an integer homology sphere, one can construct a family of closed 3-manifolds (parametrized by the positive integers), namely the cyclic branched coverings of the knot. In this paper we…

Geometric Topology · Mathematics 2007-05-23 Stavros Garoufalidis , Andrew Kricker

We introduce a multivariable Casson-Lin type invariant for links in $S^3$. This invariant is defined as a signed count of irreducible $\operatorname{SU}(2)$ representations of the link group with fixed meridional traces. For 2-component…

Geometric Topology · Mathematics 2019-09-23 Léo Bénard , Anthony Conway

Suppose Y is an integer homology 3-sphere, Taubes proved that the number of irreducible critical orbits of the perturbed Chern-Simons functional on Y, counted with signs, is equal to the algebraic intersection number of two character…

Geometric Topology · Mathematics 2021-02-09 Shaoyun Bai

We present a new invariant, called slope, of a colored link in an integral homology sphere and use this invariant to complete the signature formula for the splice of two links. We develop a number of ways of computing the slope and a few…

Geometric Topology · Mathematics 2024-03-05 Alex Degtyarev , Vincent Florens , Ana G. Lecuona

By proving a connected sum formula for the Legendrian invariant $\lambda_+$ in knot Floer homology we exhibit infinitely many transversely non simple knots.

Symplectic Geometry · Mathematics 2016-01-20 Vera Vértesi

We introduce a unified framework for counting representations of knot groups into $SU(2)$ and $SL(2, \mathbb{R})$. For a knot $K$ in the 3-sphere, Lin and others showed that a Casson-style count of $SU(2)$ representations with fixed…

Geometric Topology · Mathematics 2025-12-03 Nathan M. Dunfield , Jacob Rasmussen

We establish a relationship between the sheaf-theoretic SL(2,C) Floer cohomology HP(Y), as defined by Abouzaid and Manolescu, for Y a surgery on a small knot in S^3, and the SL(2,C) Casson invariant, as defined by Curtis. We determine a…

Geometric Topology · Mathematics 2021-12-14 Ikshu Neithalath

We bound the value of the Casson invariant of any integral homology 3-sphere $M$ by a constant times the distance-squared to the identity, measured in any word metric on the Torelli group $\T$, of the element of $\T$ associated to any…

Geometric Topology · Mathematics 2020-06-08 Nathan Broaddus , Benson Farb , Andrew Putman

Formulas previously presented for the Casson-Walker invariant are generalized to Lescop's extension. These formulas in terms of linking numbers and surgery coefficients compute the change in Lescop's invariant under crossing changes in a…

Geometric Topology · Mathematics 2007-05-23 Jeff Johannes

New methods for computing a variety of gauge theoretic invariants for homology 3-spheres are developed. These invariants include the Chern-Simons invariants, the spectral flow of the odd signature operator, and the rho invariants of…

Geometric Topology · Mathematics 2014-12-10 Hans U Boden , Christopher M Herald , Paul A Kirk , Eric P Klassen

Given a knot K and an irreducible metabelian SL(n,C) representation we establish an equality for the dimension of the first twisted cohomology. In the case of equality, we prove that the representation must have finite image and that it is…

Geometric Topology · Mathematics 2014-09-05 Hans U. Boden , Stefan Friedl

We prove the additivity of the Casson-Seiberg-Witten invariant of integral homology $S^1 \times S^3$ under fiber sum along embedded curves and embedded tori, which is the $4$-dimensional analogue of the additivity of the Casson invariant…

Geometric Topology · Mathematics 2019-10-18 Langte Ma

We define a $\mathbb{Z}_2$-valued invariant for transversely-intersecting coassociative $4$-folds equipped with spin structures. Our main result shows this invariant provides an obstruction to separating two such coassociatives through a…

Differential Geometry · Mathematics 2025-10-21 Dylan Galt

We construct an invariant $z (M) =1+a_1(A^4-1)+ a_2(A^4-1)^2+a_3(A^4-1)^3 + \cdots \in \mathbb{Q} [[A^4-1]]= \mathbb{Q} [[A+1]]$ for an integral homology $3$-sphere $M$ using a completed skein algebra and a Heegaard splitting. The invariant…

Geometric Topology · Mathematics 2017-11-21 Shunsuke Tsuji