  This work is devoted to the study of the support of a Laurent series in
several variables which is algebraic over the ring of power series over a
characteristic zero field. Our first result is the existence of a kind of
maximal dual cone of the support of such a Laurent series. As an application of
this result we provide a gap theorem for Laurent series which are algebraic
over the field of formal power series. We also relate these results to
diophantine properties of the fields of Laurent series.
