# A Symmetry of the Einstein–Friedmann Equations for Spatially Flat, Perfect Fluid, Universes

## Abstract

**:**

## 1. Introduction

## 2. The Symmetry Transformation

## 3. A Group of Symmetry Transformations

## 4. Symmetry of the Solutions

## 5. Conclusions

## Funding

## Conflicts of Interest

## References

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**MDPI and ACS Style**

Faraoni, V.
A Symmetry of the Einstein–Friedmann Equations for Spatially Flat, Perfect Fluid, Universes. *Symmetry* **2020**, *12*, 147.
https://doi.org/10.3390/sym12010147

**AMA Style**

Faraoni V.
A Symmetry of the Einstein–Friedmann Equations for Spatially Flat, Perfect Fluid, Universes. *Symmetry*. 2020; 12(1):147.
https://doi.org/10.3390/sym12010147

**Chicago/Turabian Style**

Faraoni, Valerio.
2020. "A Symmetry of the Einstein–Friedmann Equations for Spatially Flat, Perfect Fluid, Universes" *Symmetry* 12, no. 1: 147.
https://doi.org/10.3390/sym12010147