In the Wikipedia article on Hilber manifolds, it is claimed that every Hilbert manifold can be smoothly embedding onto an open subset of the model Hilbert space. However, no explicit reference is given. Does anybody know a reference.

I must honestly say that I find that result somewhat hard to believe...

In the Wikipedia article on Hilbert manifolds, it is claimed that every Hilbert manifold can be smoothly embedded onto an open subset of the model Hilbert space. However, no explicit reference is given. Does anybody know a reference.

I must honestly say that I find that result somewhat hard to believe...