We discuss the existence of de Sitter inflationary solutions for the
string-inspired fourth-derivative gravity theories with dilaton field. We
consider a space-time of arbitrary dimension D and an arbitrary parametrization
of the target space metric. The specific features of the theory in dimension
D=4 and those of the special ghost-free parametrization of the metric are
found. We also consider similar string-inspired theories with torsion and
construct an inflationary solution with torsion and dilaton for D=4. The
stability of the inflationary solutions is also investigated.Comment: 13 pages, LaTeX, no figure
