Comments on 'Regular inflationary cosmology and gauge theories of gravitation'
In this note we comment recent paper by A.V. Minkevich 'Regular inflationary cosmol-ogy and gauge theories of gravitation' on the 'bouncing' character of flat-type inflationary cosmological models within gauge theories of gravity. Recently [1] it was argued that inflationary cosmological solutions in the case of flat models within the framework of gauge theories of gravity have 'bouncing' character and they can be used in order to build regular inflationary models. Below we show that this conclusion is not valid. In spite of the fact, that oscillations (when Hubble parameter changes sign twice) could take place in course of the evolution of the Universe, such solutions necessary experience singularity in the future or in the past. Analysis of flat-type inflationary cosmological models with massive scalar field within gauge theories of gravity was carried out in the paper [2]. Qualitative analysis shows that unlike the case of General Relativity there are edges of the phase space separating 'physical' regions where Hubble parameter is real from 'unphysical' regions where Hubble parameter is complex. This allows to obtain the following conclusions: 1. At contraction stage the Hubble parameter tends to negative value depending on the mass of scalar field. 2. At expansion stage inflation is a generic feature of solutions of gauge theories of gravity cosmological equations. Our analysis was based on the idea that in the case of flat models Hubble parameter can be expressed as a function of the scalar field variables [2], namely ϕ and ˙ ϕ via cosmological equations: H =