CENTRE DE MATHEMATIQUES APPLIQUEES C.M.A.P. processus dans un milieu irregulier une approche par les formes de dirichlet p The whole paper is available as a compressed Postscript file by internet procedure FTP anonymous on host barbes.polytechnique.fr ( 129.104.4.100) in the directory pub/RI/1998 under the name seignourel_388.juin/ps.ps or by Netscape or any other www client via the CMAP www server http://www.cmap.polytechnique.fr