Using shadowing techniques we prove that the H&
eacute;non map
cle_142_TeX2GIFIEq1.gif"" alt=""$H_{a,b}(x,y)=(a-x^{2}+by,x)$"" align=""middle"" border=""0""> admits a transversal homo
clinic point for a set of parameters which is not small. For the area and orientation preserving H&
eacute;non map (corresponding to
b