Global structure of the inflationary universe

The global structure of the universe is analyzed within the framework of the chaotic inflation scenario. It is shown that under certian conditions inflation of the universe in accordance with this scenario does not have an end and may not have a beginning. Consequently, a larger part of the physical volume of the universe should always be in a state of inflation at a density of the order of the Planckian density. During inflation the universe separates into regions of exponentially large sizes. Within these regions all possible types of metastable vacuum states and all possible types of compactification, consistent with the presence of inflation are realized. The investigation is performed by employing the diffusion equation for a fluctuating scalar field in an inflating universe.