COSMOLOGICAL MODELS IN 2 SPACETIME DIMENSIONS

Various physical properties of cosmological models in 1 + 1 dimensions are investigated. We demonstrate how a hot big bang and a hot big cru nch can arise in some models. In particular, we examine why particle h orizons do not occur in matter and radiation models. We also discuss u nder what circumstances exponential inflation and matter/radiation dec oupling can happen. Finally, without assuming any particular equation of state, we show that physical singularities can occur in both untilt ed and tilted universe models if certain assumptions are satisfied, si milar to the (3 + 1)-dimensional cases.