A Symmetry of the Einstein–Friedmann Equations for Spatially Flat, Perfect Fluid, Universes
We report a symmetry property of the Einstein−Friedmann equations for spatially flat Friedmann−Lemaître−Robertson−Walker universes filled with a perfect fluid with any constant equation of state. The symmetry transformations form a one-parameter Abeli...
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Format: | Article |
Language: | English |
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MDPI AG
2020-01-01
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Series: | Symmetry |
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Online Access: | https://www.mdpi.com/2073-8994/12/1/147 |