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Usmani, A.A., Ghosh, P.P., Mukhopadhyay, U., Ray, P.C. and Ray, S. (2008) The Dark Energy Equation of State. Monthly Notices of the Royal Astronomical Society, 386, L92-L95.
https://doi.org/10.1111/j.1745-3933.2008.00468.x

has been cited by the following article:

• TITLE: Periodic Signature Change in Spacetimes of Embedding Class One

  AUTHORS: Peter K. F. Kuhfittig

  KEYWORDS: Signature Change, Oscillating Universe, Embedding Class One

  JOURNAL NAME: International Journal of Astronomy and Astrophysics, Vol.12 No.2, April 29, 2022

  ABSTRACT: The idea of an oscillating Universe has remained a topic of interest even after the discovery of dark energy. This paper confirms this idea by means of another well-established theory in general relativity, the embedding of curved spacetimes in higher-dimensional flat spacetimes: an n-dimensional Riemannian space is said to be of embedding class m if m+n is the lowest dimension of the flat space in which the given space can be embedded; here . So a four-dimensional Riemannian space is of class two and can therefore be embedded in a six-dimensional flat space. A line element of class two can be reduced to a line element of class one by a suitable coordinate transformation. The extra dimension can be either spacelike or timelike, leading to accelerating and decelerating expansions, respectively. Accordingly, it is proposed in this paper that the free parameter occurring in the transformation be a periodic function of time. The result is a mathematical model that can be interpreted as a periodic change in the signature of the embedding space. This signature change may be the best model for an oscillating Universe and complements various models proposed in the literature.