arXiv research

Study character varieties of symmetric hyperbolic knots, observing different behaviors based on symmetry type.

New knot polynomials yield simple results modulo primes.

The Dold-Whitney theorem helps classify bundles and gives a mod 4 slice obstruction.

Let $S=S_{g,p}$ be a compact, orientable surface of genus $g$ with $p$ punctures and such that $d(S):=3g-3+p>0$. The mapping class group $\textup{Mod}_S$ acts properly discontinuously on the Teichmüller space $\mathcal T(S)$ of marked hyperbolic structures on $S$. The resulting quotient $\mathcal M(S)$ is the moduli sp…

The paper solves the Nielsen realization problem for cyclic actions on surfaces.

Ozsváth, Rasmussen and Szabó constructed odd Khovanov homology. It is a link invariant which has the same reduction modulo 2 as (even) Khovanov homology. Szabó introduced a spectral sequence with mod 2 coefficients from mod 2 Khovanov homology to another link homology. He got his spectral sequence from a chain complex …

New proof shows a link problem is hard without complex links.

We analyze two braid group representations and their reductions modulo p.

We prove that the mod Z reduction of the torsion of a rational homology 3-sphere is completely determined by three data: a certain canonical spin^c structure, the linking form and a Q/Z-valued constant c. This constant is a new topological invariant of the rational homology sphere. Experimentations with lens spaces sug…

The paper compares different hashing schemes for their performance on structured data.

Torsion found in knot homology, challenging augmentation theories.

Ozsvath, Rasmussen and Szabo constructed odd Khovanov homology. It is a link invariant which has the same reduction modulo 2 as (even) Khovanov homology. Szabo introduced a spectral sequence with mod 2 coefficients from mod 2 Khovanov homology to another link homology. He got his spectral sequence from a chain complex …

A geometric construction of Sullivan's Stiefel-Whitney homology classes of a real analytic variety $X$ is given by means of the conormal cycle of an embedding of $X$ in a smooth variety. We prove that the Stiefel-Whitney classes define additive natural transformations from certain constructible functions to homology. W…

Researchers prove a complex surface is simply-connected.

Constructs integer-valued cohomology classes from graph cocycles.

Proves simple type conjecture for mod 2 Seiberg-Witten invariants.

Study of quotient groups of mapping class groups by power subgroups.

We consider two mod-p central series of the free group given by Stallings and Zassenhaus. Applying these series to definitions of Dennis Johnson's filtration of the mapping class group we obtain two mod-p Johnson filtrations. Further, we adapt the definition of the Johnson homomorphisms to obtain mod-p Johnson homomorp…

We study the Goussarov-Habiro finite type invariants theory for framed string links in homology balls. Their degree 1 invariants are computed: they are given by Milnor's triple linking numbers, the mod 2 reduction of the Sato-Levine invariant, Arf and Rochlin's $μ$ invariant. These invariants are seen to be naturally r…

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…

Let Mod(S) be the extended mapping class group of a surface S. For S the twice-punctured torus, we show that there exists an isomorphism of finite index subgroups of Mod(S) which is not the restriction of an inner automorphism. For S a torus with at least three punctures, we show that every injection of a finite index …

Mod 2 index theorem for non-orientable pin^- manifolds.

Handlebody groups are rigid under measure equivalence.

This paper introduces a new method to create mod m almost classical links from virtual knots.

Researchers compute mod 2 Seiberg-Witten invariants for spin structures and families.

Smooth approximation of integral cycles mod 2 in Riemannian manifolds.

In this paper, we construct spines, i.e., $\Mod_g$-equivariant deformation retracts, of the Teichmüller space $\T_g$ of compact Riemann surfaces of genus $g$. Specifically, we define a $\Mod_g$-stable subspace $S$ of positive codimension and construct an intrinsic $\Mod_g$-equivariant deformation retraction from $\T_g$…

Let Mod_g be the mapping class group of a genus g >= 2 surface. The group Mod_g has virtual cohomological dimension 4g-5. In this note we use a theorem of Broaddus and the combinatorics of chord diagrams to prove that H^{4g-5}(Mod_g; Q) = 0.

A new systolic inequality for mod 2 systoles is established.

In this article, we propose two algorithms for determining the Nielsen-Thurston classification of a mapping class $ψ$ on a surface $S$. We start with a finite generating set $X$ for the mapping class group and a word $ψ$ in $\langle X \rangle$. We show that if $ψ$ represents a reducible mapping class in $\Mod(S)$ then …

Let Mod_{g,b} denote the mapping class group of a surface of genus g with b punctures. Feng Luo asked in a recent preprint if there is a universal upper bound, independent of genus, for the number of torsion elements needed to generate Mod_{g,b}. We answer Luo's question by proving that 3 torsion elements suffice to ge…

We characterize convex cocompact subgroups of mapping class groups that arise as subgroups of specially embedded right-angled Artin groups. That is, if the right-angled Artin group G in Mod(S) satisfies certain conditions that imply G is quasi-isometrically embedded in Mod(S), then a purely pseudo-Anosov subgroup H of …

Paper shows ergodicity and irreducibility of mapping class group boundary representation.

Paper constructs cyclic coverings of virtual link diagrams, proving equivalence of certain maps.

The paper solves the Nielsen realization problem for high degree del Pezzo surfaces.

The paper characterizes finite metacyclic subgroups in mapping class groups of surfaces.

A new invariant for trivalent fatgraphs using homology.

Study on mod 2 Betti numbers of complex hyperplane arrangements and Milnor fiber homology.

The paper solves conditions for metacyclic actions on surfaces, including upper bounds and subgroup classifications.

We give a presentation for the baseleaf preserving mapping class group $Mod(§)$ of the punctured solenoid $§$. The generators for our presentation were introduced previously, and several relations among them were derived. In addition, we show that $Mod(§)$ has no non-trivial central elements. Our main tool is a new com…

We publish a table of primitive finite-type invariants of order less than or equal to six, for knots of ten or fewer crossings. We note certain mod-2 congruences, one of which leads to a chirality criterion in the Alexander polynomial. We state a computational result on mod-2 finite-type invariants of 2-strand string l…

Nonorientable surface mapping class group embeds quasi-isometrically in its orientable cover.

A new method using mod n covering improves systolic inequalities.

New EZ-structure maps mapping class group actions.

Multi-Output Dependence (MOD) learning is a generalization of standard classification problems that allows for multiple outputs that are dependent on each other. A primary issue that arises in the context of MOD learning is that for any given input pattern there can be multiple correct output patterns. This changes the…

Computes cohomology of rank 2 bundles, linking to skew Schur polynomials.

Mapping class groups of surfaces can be generated by torsion elements.

We give an alternative proof of the mod $p$ vanishing theorem by F.Fang of Seiberg-Witten invariants under a cyclic group action of prime order, and generalize it to the case when $b_1>0$. Although we also use the finite dimensional approximation of the monopole map as well as Fang, our method is rather geometric. Furt…