# Past-completeness of inflationary spacetimes

@article{Lesnefsky2022PastcompletenessOI,
title={Past-completeness of inflationary spacetimes},
author={Joseph Lesnefsky and Damien A Easson and Paul C. W. Davies},
journal={Physical Review D},
year={2022}
}
• Published 3 July 2022
• Mathematics
• Physical Review D
We discuss the question of whether or not inflationary spacetimes can be geodesically complete in the infinite past. Geodesic completeness is a necessary condition for averting an initial singularity during eternal inflation. It is frequently argued that cosmological models which are expanding sufficiently fast (having average Hubble expansion rate $H_{avg}>0$) must be incomplete in null and timelike past directions. This well-known conjecture relies on specific bounds on the integral of the…
1 Citations

## Figures and Tables from this paper

According to the Borde-Guth-Vilenkin (BGV) theorem an expanding region of spacetime cannot be extended to the past beyond some boundary $\mathcal{B}$. Therefore, the inflationary universe must have

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