Results 41 to 50 of about 1,268 (101)

Curvature of quaternionic skew‐Hermitian manifolds and bundle constructions

open access: yesMathematische Nachrichten, Volume 298, Issue 1, Page 87-112, January 2025.
Abstract This paper is devoted to a description of the second‐order differential geometry of torsion‐free almost quaternionic skew‐Hermitian manifolds, that is, of quaternionic skew‐Hermitian manifolds (M,Q,ω)$(M, Q, \omega)$. We provide a curvature characterization of such integrable geometric structures, based on the holonomy theory of symplectic ...
Ioannis Chrysikos   +2 more
wiley   +1 more source

On Riemannian 4‐manifolds and their twistor spaces: A moving frame approach

open access: yesMathematische Nachrichten, Volume 297, Issue 12, Page 4651-4670, December 2024.
Abstract In this paper, we study the twistor space Z$Z$ of an oriented Riemannian 4‐manifold M$M$ using the moving frame approach, focusing, in particular, on the Einstein, non‐self‐dual setting. We prove that any general first‐order linear condition on the almost complex structures of Z$Z$ forces the underlying manifold M$M$ to be self‐dual, also ...
Giovanni Catino   +2 more
wiley   +1 more source

Zero‐curvature subconformal structures and dispersionless integrability in dimension five

open access: yesJournal of the London Mathematical Society, Volume 110, Issue 6, December 2024.
Abstract We extend the recent paradigm “Integrability via Geometry” from dimensions 3 and 4 to higher dimensions, relating dispersionless integrability of partial differential equations to curvature constraints of the background geometry. We observe that in higher dimensions on any solution manifold, the symbol defines a vector distribution equipped ...
Boris Kruglikov, Omid Makhmali
wiley   +1 more source

Open String Renormalization Group Flow as a Field Theory

open access: yesFortschritte der Physik, Volume 72, Issue 11, November 2024.
Abstract This article shows that the integral flow‐lines of the RG‐flow of open string theory can be interpreted as the solitons of a Hořova–Lifshitz sigma‐model of open membranes. The authors argue that the effective background description of this model implies the g‐theorem of open string theory.
Julius Hristov
wiley   +1 more source

Heavenly metrics, hyper‐Lagrangians and Joyce structures

open access: yesJournal of the London Mathematical Society, Volume 110, Issue 5, November 2024.
Abstract In [Proc. Sympos. Pure Math., American Mathematical Society, Providence, RI, 2021, pp. 1–66], Bridgeland defined a geometric structure, named a Joyce structure, conjectured to exist on the space M$M$ of stability conditions of a CY3$CY_3$ triangulated category.
Maciej Dunajski, Timothy Moy
wiley   +1 more source

Compatible Complex Structures on Twistor Spaces

open access: yes, 2008
Let (M,g) be a Riemannian 4-manifold. The twistor space Z->M is a CP1-bundle whose total space Z admits a natural metric h. The aim of this article is to study properties of complex structures on (Z,h) which are compatible with the CP1-fibration and the ...
Deschamps, Guillaume
core   +2 more sources

Local normal forms for c-projectively equivalent metrics and proof of the Yano-Obata conjecture in arbitrary signature. Proof of the projective Lichnerowicz conjecture for Lorentzian metrics [PDF]

open access: yes, 2015
Two K\"ahler metrics on a complex manifold are called c-projectively equivalent if their $J$-planar curves coincide. These curves are defined by the property that the acceleration is complex proportional to the velocity.
Bolsinov, Alexey V.   +2 more
core   +1 more source

Uniqueness of Ricci flows from non‐atomic Radon measures on Riemann surfaces

open access: yesProceedings of the London Mathematical Society, Volume 128, Issue 6, June 2024.
Abstract In previous work (Topping and Yin, https://arxiv.org/abs/2107.14686), we established the existence of a Ricci flow starting with a Riemann surface coupled with a non‐atomic Radon measure as a conformal factor. In this paper, we prove uniqueness, settling Conjecture 1.3 of Topping and Yin (https://arxiv.org/abs/2107.14686).
Peter M. Topping, Hao Yin
wiley   +1 more source

Almost monotonicity formula for H‐minimal Legendrian surfaces in the Heisenberg group

open access: yesCommunications on Pure and Applied Mathematics, Volume 77, Issue 3, Page 1940-1957, March 2024.
Abstract We prove an almost monotonicity formula for H‐minimal Legendrian Surfaces (also called contact stationary Legendrian immersions or Hamiltonian stationary immersions) in the Heisenberg Group H2${\mathbb {H}}^2$. From this formula we deduce a Bernstein‐Liouville type theorem for H‐minimal Legendrian Surfaces.
Tristan Rivière
wiley   +1 more source

Singular CR structures of constant Webster curvature and applications

open access: yesMathematische Nachrichten, Volume 297, Issue 3, Page 943-961, March 2024.
Abstract We consider the sphere S2n+1$\mathbb {S}^{2n+1}$ equipped with its standard contact form. In this paper, we construct explicit contact forms on S2n+1∖S2k+1$\mathbb {S}^{2n+1}\setminus \mathbb {S}^{2k+1}$, which are conformal to the standard one and whose related Webster metrics have constant Webster curvature; in particular, it is positive if ...
Chiara Guidi   +2 more
wiley   +1 more source

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