Korteweg-de Vries adiabatic index solitons in barotropic open FRW cosmologies

Applying standard mathematical methods, it is explicitly shown how the Riccati equation for the Hubble parameter H(\eta) of barotropic open FRW cosmologies is connected with a Korteweg-de Vries equation for adiabatic index solitons. It is also shown how one can embed a discrete sequence of adiabatic indices of the type n^2({3/2}\gamma -1)^2 (\gamma \neq 2/3) in the sech FRW adiabatic index soliton