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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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4895143190 · Jun 202019922001200920172026
48 results for left-orderable groups

Proves HNN extensions of nilpotent groups are left-orderable, constructs non-left-orderable examples.

problem Characterizing left-orderability in HNN extensions of groups.
method Analyzes HNN extensions of torsion-free nilpotent groups and left-orderable groups.
result Constructs examples of non-left-orderable HNN extensions of left-orderable groups.

There are various results that frame left-orderability of a group as a geometric property. Indeed, the fundamental group of a 3-manifold is left-orderable whenever the first Betti number is positive; in the case that the first Betti number is zero this property is closely tied to the existence of certain nice foliation…

2010-09-21abs ↗pdf ↗

Motivated by recent activity in low-dimensional topology, we provide a new criterion for left-orderability of a group under the assumption that the group is circularly-orderable: A group GG is left-orderable if and only if G×Z/nZG \times \mathbb{Z}/n\mathbb{Z} is circularly-orderable for all n>1n > 1. This implies that eve…

2019-03-11abs ↗pdf ↗

New method detects left-orderable surgeries on knot 6_2.

problem Detecting left-orderable fundamental groups of Dehn surgeries on knots.
method Using hyperbolic PSL~(2,R)\widetilde{PSL}(2,\mathbb{R})-representations.
result All Dehn surgeries on knot 6_2 with specified slopes have left-orderable fundamental groups.

We show that the resulting manifold by rr-surgery on a large class of two-bridge knots has left-orderable fundamental group if the slope rr satisfies certain conditions. This result gives a supporting evidence to a conjecture of Boyer, Gordon and Watson that relates LL-spaces and the left-orderability of their funda…

2013-01-12abs ↗pdf ↗

3-manifolds with Heegaard 2 admit taut foliations if their fundamental group is left-orderable.

problem Characterizing 3-manifolds with taut foliations.
method Proving existence of taut foliations based on left-orderability of the fundamental group.
result 3-manifolds with Heegaard genus 2 and left-orderable fundamental group admit co-orientable taut foliations.

Bi-orderable groups from left-orderable ones, showing non-profinite properties.

problem Non-profinite properties in bi-orderability and generalized torsion elements.
method Using fiber products to construct bi-orderable groups, showing non-profinite properties.
result Bi-orderability and generalized torsion elements are not profinite properties.

New conditions for circular orderability of direct products, linking to left-orderability of groups.

problem Conditions for circular orderability of direct products GimesZ/nZG imes \mathbb{Z}/n\mathbb{Z}.
method Cohomological conditions and characterizations for left-orderability.
result New characterization for left-orderability of fundamental groups of rational homology 3-spheres.

The study characterizes elements of a group quotient and finds a non-locally indicable left-orderable group.

problem Understanding the structure and properties of a specific group quotient.
method Introduced an invariant for quasi-isometries of the positive real line and split it into units.
result Found a quotient of the quasi-isometry group of the positive real line that is left-orderable but not locally indicable.

We show that the fundamental group of the double branched cover of an infinite family of homologically thin, non-quasi-alternating knots is not left-orderable, giving further support for a conjecture of Boyer, Gordon, and Watson that an irreducible rational homology 3-sphere is an L-space if and only if its fundamental…

2013-10-07abs ↗pdf ↗

The paper extends techniques to create non-left-orderable manifolds from links with multiple boundary components.

problem Creating infinite families of non-left-orderable manifolds from Dehn fillings.
method Order-detection of slopes to generalize techniques for multiple boundary components.
result Produces an infinite family of non-left-orderable Dehn fillings for hyperbolic links, including the Whitehead link.

New proof shows left orderability of 3-manifold groups with specific foliations.

problem Left orderability of 3-manifold groups with co-orientable taut foliations.
method Analyzes co-orientable taut foliations with orderable cataclysm to prove left orderability of 3-manifold fundamental groups.
result Proves left orderability of 3-manifold groups with specific foliations.

New description of (1,1)(1,1) L-space knots leads to non-left-orderable surgeries.

problem Characterizing and understanding (1,1)(1,1) L-space knots.
method Analyzing coherent reduced (1,1)(1,1)-diagrams to describe (1,1)(1,1) L-space knots and proving non-left-orderable fundamental groups.
result Any L-space obtained by Dehn surgery on a (1,1)(1,1)-knot in S3S^3 has a non-left-orderable fundamental group.

We develop a method to show the fundamental group of the double branched covering of a link is not left-orderable by introducing the notion of the coarse presentation. As in the usual group presentations, a coarse presentation is given by a set of generators and relations, but inequalities are allowed as relations. By …

2011-06-08abs ↗pdf ↗

Motivated by Clay and Watson's question on left-orderability of the fundamental group of the resultant space of an rr'-surgery on the (p,q)(p, q)-cable knots for r(pqpq,pq)r' \in (pq-p-q,pq), this paper proves by elementary means that for specific pairs of (p,q)(p,q)-cable knots of torus knots, r[pq1,pq]r' \in [pq-1,pq] gives a surgery yi…

2016-10-04abs ↗pdf ↗

A slope rr is called a left orderable slope of a knot KS3K \subset S^3 if the 3-manifold obtained by rr-surgery along KK has left orderable fundamental group. Consider two-bridge knots C(2m,±2n)C(2m, \pm 2n) and C(2m+1,2n)C(2m+1, -2n) in the Conway notation, where m1m \ge 1 and n2n \ge 2 are integers. By using \textit{continuous} f…

2020-03-02abs ↗pdf ↗

Let K be a knot in the 3--sphere. An r-surgery on K is left-orderable if the resulting 3--manifold K(r) of the surgery has left-orderable fundamental group, and an r-surgery on K is called an L-space surgery if K(r) is an L-space. A conjecture of Boyer, Gordon and Watson says that non-reducing surgeries on K can be cla…

2013-01-24abs ↗pdf ↗

We show that the 3-fold cyclic branched cover of any genus 2 two-bridge knot K[2q,2s,2t,2l]K_{[-2q,2s,-2t,2l]} is an L-space and its fundamental group is not left-orderable. Therefore the family of 3-fold cyclic branched cover of any genus 2 two-bridge knot K[2q,2s,2t,2l]K_{[-2q,2s,-2t,2l]} verifies the LL-space conjecture. We also show that…

2018-01-08abs ↗pdf ↗

We show that several torsion free 3-manifold groups are not left-orderable. Our examples are groups of cyclic branched covers of S^3 branched along links. The figure eight knot provides simple nontrivial examples. The groups arising in these examples are known as Fibonacci groups which we show not to be left-orderable.…

2003-02-10abs ↗pdf ↗

In a recent paper Y. Hu has given a sufficient condition for the fundamental group of the r-th cyclic branched covering of S^3 along a prime knot to be left-orderable in terms of representations of the knot group. Applying her criterion to a large class of two-bridge knots, we determine a range of the integer r>1 for w…

2013-11-18abs ↗pdf ↗

Study proves non-left-orderability of 3-manifolds derived from specific knots.

problem Proving non-left-orderability of knot groups in 3-manifolds.
method Analyzing fundamental groups of cyclic branched covers of pretzel knots.
result Non-left-orderability of fundamental groups of nn-fold cyclic branched covers of P(3,3,2k1)P(3,-3,-2k-1) for all integers kk and n1n\ge 1.

Let G be a group and let O_G denote the set of left orderings on G. Then O_G can be topologized in a natural way, and we shall study this topology to answer three conjectures. In particular we shall show that O_G can never be countably infinite. Furthermore in the case G is a countable nonabelian free group, we shall s…

2006-07-19abs ↗pdf ↗

A left order on a magma (e.g., semigroup) is a total order of its elements that is left invariant under the magma operation. A natural topology can be introduced on the set of all left orders of an arbitrary magma. We prove that this topological space is compact. Interesting examples of nonassociative magmas, whose spa…

2006-06-11abs ↗pdf ↗

We show that the fundamental group of the 33-manifold obtained by pq\frac{p}{q}-surgery along the (n2)(n-2)-twisted (3,3m+2)(3,3m+2)-torus knot, with n,m1n,m \ge 1, is not left-orderable if pq2n+6m3\frac{p}{q} \ge 2n + 6m-3 and is left-orderable if pq\frac{p}{q} is sufficiently close to 00.

2018-09-04abs ↗pdf ↗

Previous work of the authors establishes a criterion on the fundamental group of a knot complement that determines when Dehn surgery on the knot will have a fundamental group that is not left-orderable. We provide a refinement of this criterion by introducing the notion of a decayed knot; it is shown that Dehn surgery …

2011-03-11abs ↗pdf ↗

The paper constructs paths of SL2(R) representations for pretzel knots and shows left-orderability conditions.

problem Left-orderability of knot surgery manifolds.
method Explicit construction of continuous paths of SL2(R) representations.
result Fundamental groups of certain knot surgeries are left-orderable.

Study slopes on knot manifolds to understand their fundamental groups.

problem Characterize slopes on knot manifolds to determine fundamental group properties.
method Develops new order-detection notions, parallels existing slope detection methods, and uses dynamics of 3-manifold group actions.
result Conjectured structure theorems connecting Heegaard-Floer homology and foliation dynamics to left-orderability.

We provide an alternative proof of a sufficient condition for the fundamental group of the nthn^{th} cyclic branched cover of S3S^3 along a prime knot KK to be left-orderable, which is originally due to Boyer-Gordon-Watson. As an application of this sufficient condition, we show that for any (p,q)(p,q) two-bridge knot, wi…

2013-11-13abs ↗pdf ↗