Results 21 to 30 of about 1,021 (98)

Deformations of nearly Kähler instantons [PDF]

open access: yes, 2016
We formulate the deformation theory for instantons on nearly Kähler six-manifolds using spinors and Dirac operators. Using this framework we identify the space of deformations of an irreducible instanton with semisimple structure group with the kernel of
A. Clarke   +42 more
core   +2 more sources

Harmonic G-structures

open access: yes, 2007
For closed and connected subgroups G of SO(n), we study the energy functional on the space of G-structures of a (compact) Riemannian manifold M, where G-structures are considered as sections of the quotient bundle O(M)/G.
F. MARTÍN CABRERA   +9 more
core   +1 more source

SU(3)-instantons and $G_2, Spin(7)$-heterotic string solitons

open access: yes, 2005
Necessary and sufficient conditions to the existence of a hermitian connection with totally skew-symmetric torsion and holonomy contained in SU(3) are given.
Agricola   +50 more
core   +1 more source

Realising Mutated Hilltop Inflation in Supergravity

open access: yes, 2019
We present $\mathcal{N}=1$ supergravity models of mutated hilltop inflation (MHI) for both large and small field sectors. Models with canonical kinetic terms are developed based on a shift symmetric K\"ahler potential in inflaton superfield, and with a ...
Pal, Supratik, Pinhero, Tony
core   +1 more source

Degree theory for 4‐dimensional asymptotically conical gradient expanding solitons

open access: yesCommunications on Pure and Applied Mathematics, Volume 79, Issue 5, Page 1151-1298, May 2026.
Abstract We develop a new degree theory for 4‐dimensional, asymptotically conical gradient expanding solitons. Our theory implies the existence of gradient expanding solitons that are asymptotic to any given cone over S3$S^3$ with non‐negative scalar curvature. We also obtain a similar existence result for cones whose link is diffeomorphic to S3/Γ$S^3/\
Richard H. Bamler, Eric Chen
wiley   +1 more source

Nearly Kähler 6-Manifolds with Reduced Holonomy

open access: yes, 2001
International audienceWe consider a complete six-dimensional nearly Kähler manifold together with the first canonical Hermitian connection. We show that if the holonomy of this connection is reducible, then the manifold endowed with a modified metric and
Belgun, Florin, Moroianu, Andrei
core   +3 more sources

The universal family of punctured Riemann surfaces is Stein

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract We show that the universal Teichmüller family V(g,n)$V(g,n)$ of compact Riemann surfaces of genus g⩾0$g\geqslant 0$ with n>0$n>0$ punctures is a Stein manifold. We describe its basic function‐theoretic properties and pose some challenging questions. We show, in particular, that the space of fibrewise algebraic functions on the universal family
Franc Forstnerič
wiley   +1 more source

On the K‐stability of blow‐ups of projective bundles

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 5, May 2026.
Abstract We investigate the K‐stability of certain blow‐ups of P1$\mathbb {P}^1$‐bundles over a Fano variety V$V$, where the P1$\mathbb {P}^1$‐bundle is the projective compactification of a line bundle L$L$ proportional to −KV$-K_V$ and the center of the blow‐up is the image along a positive section of a divisor B$B$ also proportional to L$L$. When V$V$
Daniel Mallory
wiley   +1 more source

Gauge theory in dimension $7$

open access: yes, 2009
We first review the notion of a $G_2$-manifold, defined in terms of a principal $G_2$ ("gauge") bundle over a $7$-dimensional manifold, before discussing their relation to supergravity. In a second thread, we focus on associative submanifolds and present
Frederik Witt   +4 more
core   +1 more source

Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the String‐Theoretical Swampland Programme

open access: yesFortschritte der Physik, Volume 74, Issue 4, April 2026.
Abstract String theory has strong implications for cosmology, implying the absence of a cosmological constant, ruling out single‐field slow‐roll inflation, and that black holes decay. The origins of these statements are elucidated within the string‐theoretical swampland programme.
Kay Lehnert
wiley   +1 more source

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