arXiv research

Study trisections of non-orientable 4-manifolds with boundary.

The paper extends trisection theory to non-orientable 4-manifolds using colored triangulations.

Study on non-orientable surfaces and inscribed rectangles in 4-manifolds.

New singularities and fibrations in non-orientable 4-manifolds.

Gay and Kirby recently introduced the concept of a trisection for arbitrary smooth, oriented closed 4-manifolds, and with it a new topological invariant, called the trisection genus. This paper improves and implements an algorithm due to Bell, Hass, Rubinstein and Tillmann to compute trisections using triangulations, a…

Non-orientable 4-manifolds are simple branched coverings of RP^4 and twisted S^3-bundles.

We find conditions under which a non-orientable closed surface S embedded into an orientable closed 4-manifold X can be represented by a connected sum of an embedded closed surface in X and an unknotted projective plane in a 4-sphere. This allows us to extend the Gabai 4-dimensional light bulb theorem and the Auckly-Ki…

The paper studies $ext{Pin}^{\pm}$-structures on non-oriented 4-manifolds via Lefschetz fibrations.

For a closed 4-manifold $X$ and a knot $K$ in the boundary of punctured $X$, we define $γ_X^0(K)$ to be the smallest first Betti number of non-orientable and null-homologous surfaces in punctured $X$ with boundary $K$. Note that $γ^0_{S^4}$ is equal to the non-orientable 4-ball genus and hence $γ^0_X$ is a generalizati…

New non-orientable 4-manifolds created via knotting operations.

We investigate constraints on embeddings of a non-orientable surface in a $4$-manifold with the homology of $M \times I$, where $M$ is a rational homology $3$-sphere. The constraints take the form of inequalities involving the genus and normal Euler class of the surface, and either the Ozsváth--Sazbó $d$-invariants or …

Study shows how any group can be fundamental of a non-orientable 4-manifold with exotic structure.

This paper studies Dirac operators on end-periodic spin manifolds of dimension at least 4. We provide a sufficient condition for such an operator to be Fredholm for a generic end-periodic metric; this condition is shown to be necessary in dimension 4. We make use of end-periodic Dirac operators to give an analytical in…

We construct here two new examples of non-orientable, non-compact, hyperbolic 4-manifolds. The first has minimal volume $v_m = 4π^2/3$ and two cusps. This example has the lowest number of cusps among known minimal volume hyperbolic 4-manifolds. The second has volume $2\cdot v_m$ and one cusp. It has lowest volume among…

Algorithm converts Kirby diagrams to trisection diagrams for 4-manifolds.

We show that for any nonzero class $A$ in $H_2(X; \mathbb{Z}_2)$ in a rational 4-manifold $X$, $A$ is represented by a nonorientable embedded Lagrangian surface L (for some symplectic structure) if and only if $P(A)\equiv (L) (mod\ 4)$; where $P(A)$ denotes the mod 4 valued Pontrjagin square of $A$.

Study on 4-manifolds with positive scalar curvature.

In this paper, we investigate existence of inequivalent smooth structures on closed smooth non-orientable 4-manifolds building upon results of Akbulut, Cappell-Shaneson, Fintushel-Stern, Gompf, and Stolz. We add to the number of known constructions and provide new examples of exotic manifolds that are obtained as an ap…

Every 4-dimensional infrasolvmanifold $M$ with $β_1(M;\mathbb{Q})>0$ or which is flat or has one of the geometries $\mathbb{N}il^4$, $\mathbb{S}ol_{m,n}^4$, or $\mathbb{S}ol_0^4$ bounds. However there are non-orientable $\mathbb{S}ol_1^4$-manifolds which do not bound. The question remains open for $\mathbb{N}il^3\times…

The study proves exotic smooth structures and equivalent genus functions in 4-manifolds.

The paper classifies surfaces in 4-manifolds up to concordance.

Motivated by M. Scharlemann and A. Thompson's definition of thin position of 3-manifolds, we define the width of a handle decomposition a 4-manifold and introduce the notion of thin position of a compact smooth 4-manifold. We determine all manifolds having width equal to $\{1,\dots, 1\}$, and give a relation between th…

We study the space of positive scalar curvature (psc) metrics on a 4-manifold, and give examples of simply connected manifolds for which it is disconnected. These examples imply that concordance of psc metrics does not imply isotopy of such metrics. This is demonstrated using a modification of the 1-parameter Seiberg-W…

We show that if $M$ is an orientable 4-dimensional infrasolvmanifold and either $β=β_1(M;\mathbb{Q})\geq2$ or $M$ is a $\mathbb{S}ol_0^4$- or a $\mathbb{S}ol_{m,n}^4$-manifold (with $m\not=n$) then $M$ is parallelizable. There are non-parallelizable examples with $β=1$ for each of the other solvable Lie geometries $\ma…

Paper extends Miyazawa's construction to more 4-manifolds, finding exotic involutions and embeddings.

Log-symplectic structures are Poisson structures that are determined by a symplectic form with logarithmic singularities. We construct moduli spaces of curves with values in a log-symplectic manifold. Among the applications, we classify symplectically ruled log-symplectic $4$ manifolds (both orientable and non-orientab…

The paper embeds 4-manifolds into CP^2 x CP^1 using Lefschetz fibrations.

For $d\geq 2$, the regular genus of a closed connected PL $d$-manifold $M$ is the least genus (resp., half of the genus) of an orientable (resp., a non-orientable) surface into which a crystallization of $M$ imbeds regularly. The regular genus of every orientable surface equals its genus, and the regular genus of every…

Geometrically computes cohomotopy groups for higher-dimensional manifolds.

New invariants from Seiberg-Witten theory for 3-spheres with involution.

Using an obstruction based on Donaldson's theorem on the intersection forms of definite 4-manifolds, we determine which connected sums of lens spaces smoothly embed in S^4. We also find constraints on the Seifert invariants of Seifert 3-manifolds which embed in S^4 when either the base orbifold is non-orientable or the…

Detects exotic surfaces without smooth invariants, providing first example of knotted RP².

This paper calculates the non-orientable 4-genus for knots with 10 crossings.

Study curves in non-orientable surfaces with specific intersection properties.

Analog of Kauffman bracket for non-orientable knots in thickened surface.

New method finds non-orientable knotted surfaces in 4D.

Researchers refine the non-orientable $4$-genus of torus knots using Batson's surfaces.

Minimal stretch factor for non-orientable surfaces is small.

The aim of this work is to adapt the complex analytic methods originating in modern Oka theory to the study of non-orientable conformal minimal surfaces in $\mathbb{R}^n$ for any $n\ge 3$. These methods, which we develop essentially from the first principles, enable us to prove that the space of conformal minimal immer…

Researchers compute bounds and formulas for non-orientable 4-genus of torus knots.

Presentations for involutions on non-orientable surfaces up to genus 5.

Polynomial-time algorithm finds short non-orientable loops intersecting graph edges up to 30 times.

Simplified presentations for non-orientable surface mapping class groups.

Paper proves achiral Lefschetz fibrations from non-orientable Lefschetz fibrations.

New invariant distinguishes non-orientable surfaces.

Study on loops on non-orientable surfaces, determining cardinality and order.

We prove a version of the classical Runge and Mergelyan uniform approximation theorems for non-orientable minimal surfaces in Euclidean 3-space R3. Then, we obtain some geometric applications. Among them, we emphasize the following ones: 1. A Gunning-Narasimhan type theorem for non-orientable conformal surfaces. 2. An …

Study homology groups for non-orientable surfaces with boundary.