The classical polynomial interpolation problem in several variables can be
generalized to the case of points with greater multiplicities. What is known,
as yet, is essentially concentrated in the Alexander-Hirschowitz Theorem which
says that a general collection of double points in P^r gives independent
conditions on the linear system L of the hypersurfaces of degree d, with a well
known list of exceptions. We present a new proof of this theorem which consists
in performing degenerations of P^r and analyzing how L degenerates.Comment: 15 page