Editing Randall–Sundrum model (section)

==Prior models==
In 1998/99 Merab Gogberashvili published on [[arXiv]] a number of articles on a very similar theme.<ref>M. Gogberashvili, "Hierarchy problem in the shell universe model", [https://arxiv.org/abs/hep-ph/9812296 arXiv:hep-ph/9812296].</ref><ref>M. Gogberashvili, "Our world as an expanding shell", [https://arxiv.org/abs/hep-ph/9812365 arXiv:hep-ph/9812365].</ref><ref>M. Gogberashvili, "Four dimensionality in noncompact Kaluza-Klein model", [https://arxiv.org/abs/hep-ph/9904383 arXiv:hep-ph/9904383].</ref> He showed that if the Universe is considered as a thin shell (a mathematical [[synonym]] for "brane") expanding in 5-dimensional space, then there is a possibility to obtain one scale for particle theory corresponding to the 5-dimensional [[cosmological constant]] and Universe thickness, and thus to solve the hierarchy problem. It was also shown that four-dimensionality of the Universe is the result of [[Stability theory|stability]] requirement, since the extra component of the [[Einstein field equations]] giving the localized solution for [[matter]] fields coincides with one of the conditions of stability.