arXiv research

New rational homology 3-spheres found that can't bound definite 4-manifolds.

Integer homology 3-spheres have irreducible SU(2) representations.

For smooth embeddings of an integral homology 3-sphere in the 6-sphere, we define an integer invariant in terms of their Seifert surfaces. Our invariant gives a bijection between the set of smooth isotopy classes of such embeddings and the integers. It also gives rise to a complete invariant for homology bordism classe…

The study confirms conjectures about slopes of knots using knot Floer homology.

The paper constructs new rational homology 3-spheres bounding rational homology 4-balls.

Paper finds infinitely many 3-spheres without nice orderings.

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 nontrivial knots in the 3-sphere never produces an L-space. The proof uses bordered Flo…

The SU(3)-Casson invariant for integral homology 3-spheres as studied by Boden-Herald possesses a 'spectral flow obstruction' to being an integer valued invariant which depends only on the non-degenerate (perturbed) moduli space of flat SU(3)-connections. This obstruction is the non-trivial spectral flow of a family of…

We construct hyperbolic integer homology 3-spheres where the injectivity radius is arbitrarily large for nearly all points of the manifold. As a consequence, there exists a sequence of closed hyperbolic 3-manifolds which Benjamini-Schramm converge to H^3 whose normalized Ray-Singer analytic torsions do not converge to …

We define Pin(2)-equivariant Seiberg-Witten Floer homology for rational homology 3-spheres equipped with a spin structure. The analogue of Froyshov's correction term in this setting is an integer-valued invariant of homology cobordism whose mod 2 reduction is the Rokhlin invariant. As an application, we show that there…

New homology $q_2$ from 3D cobordism to integers.

Identifies a mod-$p$ triple cup product for rational homology 3-spheres with specific first homology.

We prove that the quantum SO(3)-invariant of an arbitrary 3-manifold $M$ is always an algebraic integer, if the order of the quantum parameter is co-prime with the order of the torsion part of $H_1(M,\BZ)$. An even stronger integrality, known as cyclotomic integrality, was established by Habiro for integral homology 3-…

The paper shows how to transform certain 3D shapes into hyperbolic ones.

New algorithm for recognizing 3-spheres using Groebner basis methods.

Proves SU(2) representations for certain 3-spheres with embedded tori.

In 1985 lectures at MSRI, A. Casson introduced an interesting integer valued invariant for any oriented integral homology 3-sphere Y via beautiful constructions on representation spaces (see [1] for an exposition). The Casson invariant λ(Y) is roughly defined by measuring the oriented number of irreducible representati…

The paper shows links with 2 components are not smoothly slice in a specific 4-manifold.

We use Heegaard Floer homology with twisted coefficients to define numerical invariants for arbitrary closed 3-manifolds equipped torsion spin$^c$ structures, generalising the correction terms (or $d$--invariants) defined by Ozsváth and Szabó for integer homology 3-spheres and, more generally, for 3-manifolds with stan…

Study $p$-torsion growth in covers of 3-manifolds, proving Iwasawa formulas.

New exotic 4-manifolds found from knot invariants.

We prove that the Witten-Reshetikhin-Turaev (WRT) SO(3) invariant of an arbitrary 3-manifold M is always an algebraic integer. Moreover, we give a rational surgery formula for the unified invariant dominating WRT SO(3) invariants of rational homology 3-spheres at roots of unity of order co-prime with the torsion. As an…

The following is a long-standing open question: "If the zero-framed surgeries on two knots in the 3-sphere are integral homology cobordant, are the knots themselves concordant?" We show that an obvious rational version of this question has a negative answer. Namely, we give examples of knots whose zero-framed surgeries…

This paper concerns the problem of existence of taut foliations among 3-manifolds. Since the contribution of David Gabai, we know that closed 3-manifolds with non-trivial second homology group admit a taut foliations. The essential part of this paper focuses on Seifert fibered homology 3-spheres. The result is quite di…

This paper realises the Khovanov homology of a link in the 3-sphere as a Lagrangian Floer cohomology group, establishing a conjecture of Seidel and the second author. The starting point is the previously established formality theorem for the symplectic arc algebra over a field k of characteristic zero. Here we prove th…

Finite group actions on surfaces extend to 3-manifolds.

We use Floer's exact triangle to study the u-map (cup product with the 4-dimensional class) in the Floer cohomology groups of admissible SO(3) bundles over closed, oriented 3-manifolds. In the case of non-trivial bundles we show that (u^2-64)^n = 0 for some positive integer n. For homology 3-spheres Y the same holds fo…

Study on 3-sphere Goeritz group's twisted first homology group.

Study how Dehn surgery affects surfaces with minimal Thurston norm.

We show that a graph manifold which is a Z-homology 3-sphere not homeomorphic to either the 3-sphere or the Poincaré homology 3-sphere admits a horizontal foliation. This combines with known results to show that the conditions of not being an L-space, of having a left-orderable fundamental group, and of admitting a co-…

The paper defines and calculates stabilization distances between surfaces in 4-manifolds.

The article provides formulas for homological blocks of Seifert fibered homology 3-spheres.

This paper computes the second quandle homology group of knot n-quandles.

The paper explores left-orderable groups in branched cyclic covers with taut foliations.

Classifies SL(2;C) representations of a Brieskorn homology 3-sphere.

Problems of knot classification and manifold properties are shown to be NP-complete.

Study finite type invariants for knots in rational homology 3-spheres.

The paper examines conditions for contact surgeries on rational homology 3-spheres.

Study invariants of $\mathbb{Z}/p$-homology 3-spheres from abelianization of mapping class groups.

The study examines hyperbolic 3-manifolds with uniform spectral gaps for coclosed 1-forms.

This work extends knot homology theory to links, proving exact triangles and categorifying link signatures.

We show that the perturbative ${\frak g}$ invariant of rational homology 3-spheres can be recovered from the LMO invariant for any simple Lie algebra ${\frak g}$, i.e, the LMO invariant is universal among the perturbative invariants. This universality was conjectured in [25]. Since the perturbative invariants dominate …

New invariant fully describes finite type invariants of knots in homology 3-spheres.

The cosmetic crossing conjecture (also known as the "nugatory crossing conjecture") asserts that the only crossing changes that preserve the oriented isotopy class of a knot in the 3-sphere are nugatory. We use the Dehn surgery characterization of the unknot to prove this conjecture for knots in integer homology sphere…

We prove Mayberry-Murasugi's formula for links in homology 3-spheres, which was proved before only for links in the 3-sphere. Our proof uses Franz-Reidemeister torsions.

Two non-Morse-Bott Chern-Simons functions on homology 3-spheres.

We give a new construction of monopole Floer homology for spin-c rational homology 3-spheres. As applications we define two invariants of certain smooth compact 4-manifolds with b_1=1 and b^+=0.

Researchers compute Reidemeister torsion for a specific 3-sphere.