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Related papers: On a proof of the 10/8-conjecture

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Given a closed contact 3-manifold with a compatible Riemannian metric, we show that if the sectional curvature is 1/4-pinched, then the contact structure is universally tight. This result improves the Contact Sphere Theorem in [EKM12],…

Differential Geometry · Mathematics 2013-04-19 Jian Ge , Yang Huang

We investigate the $\mathrm{Pin}^-(2)$-monopole invariants of symplectic $4$-manifolds and K\"{a}hler surfaces with real structures. We prove the nonvanishing theorem for real symplectic $4$-manifolds which is an analogue of Taubes'…

Differential Geometry · Mathematics 2021-04-06 Nobuhiro Nakamura

We study the types of non-integrable $\mathrm{G}$-structures on Riemannian manifolds. In particular, geometric types admitting a connection with totally skew-symmetric torsion are characterized. 8-dimensional manifolds equipped with a…

Differential Geometry · Mathematics 2007-05-23 Thomas Friedrich

We show an alternative construction of the first example of a simply-connected compact symplectic non-formal 8-manifold given in arXiv:math/0506449. We also give an alternative proof of its non-formality using higher order Massey products.

Symplectic Geometry · Mathematics 2011-06-10 Gil R. Cavalcanti , Marisa Fernandez , Vicente Munoz

We construct left invariant quaternionic contact (qc) structures on Lie groups with zero and non-zero torsion and with non-vanishing quaternionic contact conformal curvature tensor, thus showing the existence of non-flat quaternionic…

Differential Geometry · Mathematics 2010-09-15 Luis C. de Andrés , Marisa Fernández , Stefan Ivanov , José A. Santisteban , Luis Ugate , Dimiter Vassilev

Kreck proved that two $2q$-manifolds are stably diffeomorphic if and only if they admit normally bordant normal $(q-1)$-smoothings over the same normal $(q-1)$-type $(B,\xi)$. We show that stable diffeomorphism can be replaced by…

Geometric Topology · Mathematics 2024-02-22 Csaba Nagy

We exhibit surprising relations between higher spin theory and nonlinear realizations of the supergroup $OSp(1|8)$, a minimal superconformal extension of N=1, 4D supersymmetry with tensorial charges. We construct a realization of $OSp(1|8)$…

High Energy Physics - Theory · Physics 2011-07-19 Evgeny Ivanov , Jerzy Lukierski

In this note we prove that a four-dimensional compact oriented half-confor\-mally flat Riemannian manifold $M^4$ is topologically $\mathbb{S}^{4}$ or $\mathbb{C}\mathbb{P}^{2},$ provided that the sectional curvatures all lie in the interval…

Differential Geometry · Mathematics 2020-03-17 R. Diógenes , E. Ribeiro , E. Rufino

Liu and Piccirillo developed a combinatorial argument that employs the 10/8-theorem to demonstrate that certain manifolds cannot be obtained via Dehn surgery on a knot. We extend their approach by creating additional examples using…

Geometric Topology · Mathematics 2025-05-27 Soheil Azarpendar

We discuss the cobordism type of spin manifolds with nonnegative sectional curvature. We show that in each dimension $4k \geq 12$, there are infinitely many cobordism types of simply connected and nonnegatively curved spin manifolds.…

Differential Geometry · Mathematics 2016-07-14 Martin Herrmann , Nicolas Weisskopf

We establish a correspondence between trisections of smooth, compact, oriented $4$--manifolds with connected boundary and diagrams describing these trisected $4$--manifolds. Such a diagram comes in the form of a compact, oriented surface…

Geometric Topology · Mathematics 2017-07-27 Nickolas A. Castro , David T. Gay , Juanita Pinzón-Caicedo

Rudyak's conjecture states that for any degree one map $f:M\to N$ between oriented closed manifolds there is the inequality $\cat (M)\ge \cat(N)$ for the Lusternik-Shnirelmann category. We prove the Rudyak's conjecture for $ n$-dimensional…

Algebraic Topology · Mathematics 2026-04-13 Alexander Dranishnikov , Deep Kundu

We show that if a compact, connected, and oriented $n$-manifold $M$ without boundary admits a non-constant non-injective uniformly quasiregular self-map, then the dimension of the real singular cohomology ring $H^*(M; \mathbb{R})$ of $M$ is…

Complex Variables · Mathematics 2022-01-12 Ilmari Kangasniemi

Islambouli showed that there exist infinitely many 4-manifolds admitting non-isotopic trisections using a Nielsen equivalence, which can be used to construct non-isotopic Heegaard splittings. In this paper, we show that there exist…

Geometric Topology · Mathematics 2024-09-04 Tsukasa Isoshima , Masaki Ogawa

We prove a Hitchin-Thorpe inequality for noncompact 4-manifolds with foliated geometry at infinity by extending on previous work by Dai and Wei. After introducing the objects at hand, we recall some preliminary results regarding the…

Differential Geometry · Mathematics 2016-05-13 Ahmed J. Zerouali

We deduce some formulas for the spin invariants of the connected sum of an arbitrary 4-manifold X, b^+ _2(X) > 0 $ with $\overline {CP^2}$ in terms of the spin invariants of $X$ and apply this to prove the Van de Ven conjecture.

alg-geom · Mathematics 2008-02-03 Victor Pidstrigatch

We construct closed, aspherical, smooth 4-manifolds that are homeomorphic but not diffeomorphic. These provide counterexamples to a smooth analog of the Borel conjecture in dimension four. Our technique is to apply the `reflection group…

Geometric Topology · Mathematics 2026-05-06 Michael Davis , Kyle Hayden , Jingyin Huang , Daniel Ruberman , Nathan Sunukjian

We present several structural results on closed, nonorientable, smooth $4$--manifolds, extending analogous results and machinery for the orientable case. We prove the existence of simplified broken Lefschetz fibrations and simplified…

Geometric Topology · Mathematics 2026-02-20 R. İnanç Baykur , Porter Morgan

In this paper, we prove several rigidity results for complete noncompact manifolds with nonnegative intermediate curvatures. We show that when either $3\leq n\leq 5$, $1\leq m\leq n-1$, or $6\leq n\leq 7$, $m\in \{1,n-1,n-2\}$, any manifold…

Differential Geometry · Mathematics 2026-04-30 Jingche Chen , Han Hong

We prove that a variety of examples of minimal complex surfaces admit exotic diffeomorphisms, providing the first known instances of exotic diffeomorphisms of irreducible 4-manifolds. We also give sufficient conditions for the boundary Dehn…

Geometric Topology · Mathematics 2025-06-30 David Baraglia , Hokuto Konno