Gürses, MetinYaghoub, HeydarzadeTekin, B.2021-02-122021-02-1220201475-7516http://hdl.handle.net/11693/55108We show that (1) the Einstein field equations with a perfect fluid source admit a nonlinear superposition of two distinct homogenous Friedman-Lemaitre-Robertson-Walker (FLRW) metrics as a solution, (2) the superposed solution is an inhomogeneous geometry in general, (3) it reduces to a homogeneous one in the two asymptotes which are the early and the late stages of the universe as described by two different FLRW metrics, (4) the solution possesses a scale factor inversion symmetry and (5) the solution implies two kinds of topology changes: one during the time evolution of the superposed universe and the other occurring in the asymptotic region of space.EnglishCosmic singularityCosmological phase transitionsCosmology of theories beyond the SMDark energy theoryArticle10.1088/1475-7516/2020/06/060