Local Type I Metrics with Holonomy in G₂*

• Published in: Symmetry, Integrability and Geometry: Methods and Applications
• Date: 2018
• Main Authors: Fino, A., Kath, I.
• Format: Article
• Language: English
• Published: Інститут математики НАН України 2018
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/209769
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Local Type I Metrics with Holonomy in G₂* / A. Fino, I. Kath // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 14 назв. — англ.

By [arXiv:1604.00528], a list of possible holonomy algebras for pseudo-Riemannian manifolds with an indecomposable torsion-free G₂*-structure is known. Here, indecomposability means that the standard representation of the algebra on R⁴,³ does not leave invariant any proper non-degenerate subspace. The dimension of the socle of this representation is called the type of the Lie algebra. It is equal to one, two, or three. In the present paper, we use Cartan's theory of exterior differential systems to show that all Lie algebras of Type I from the list in [arXiv:1604.00528] can indeed be realised as the holonomy of a local metric. All these Lie algebras are contained in the maximal parabolic subalgebra p₁ that stabilises one isotropic line of R⁴,³. In particular, we realise p₁ by a local metric.