Curvature of quaternionic skew‐Hermitian manifolds and bundle constructions
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
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
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
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
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
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]
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
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
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
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

