2 -&gt; V
|
| is a projection.  One sees then that the image of a submersion is
| an open subset (a submersion is in fact an open mapping).  We say
| that f is a &quot;submersion&quot; if it is a submersion at every point.
|
| For manifolds modeled on Banach spaces, we have the usual criterion
| for immersions and submersions in terms of the derivative.
|
| Proposition 2.2.  Let X, Y be manifolds of class C^p (p &gt;= 1) modeled on Banach spaces.
|
|                   Let f : X -&gt; Y be a C^p-morphism.  L