collaborators

5 papers

math.DG2026

Möbius-Type Structures in Non-Orientable Singular Semi-Riemannian Manifolds

Nathalie E. Rieger

Our objective is to illuminate the global structure of non-orientable manifolds with signature-changing metrics, with particular emphasis on global topological obstructions. Using…

math.DG2026

A Transformation Theorem for Transverse Signature-Type Changing Semi-Riemannian Manifolds

W. Hasse, N. E. Rieger

In the early eighties Hartle and Hawking put forth that signature-type change may be conceptually interesting, paving the way to the so-called 'no boundary' proposal for the initia…

gr-qc2025

A Conceptual Introduction To Signature Change Through a Natural Extension of Kaluza-Klein Theory

Vincent Moncrief, Nathalie E. Rieger

We propose an extension of basic Kaluza-Klein theory in which the higher-dimensional Lorentzian manifold develops a Cauchy horizon rather than remaining globally hyperbolic as in t…

math.DG2025

Pseudo-timelike loops in signature changing semi-Riemannian manifolds with a transverse radical

N. E. Rieger, W. Hasse

In 1983, Hartle and Hawking proposed the no-boundary proposal, suggesting that the universe has no beginning in the sense of a spacetime singularity or boundary. Nevertheless, ther…

math.DG2025

Embedding Signature-Changing Manifolds: A Braneworld and Kaluza-Klein Perspective

N. E. Rieger

We investigate a class of semi-Riemannian manifolds characterized by smooth metric signature changes with a transverse radical. This class includes spacetimes relevant to cosmologi…