>>574　補足
http://www.maths.ed.ac.uk/~aar/papers/exoticsmooth.pdf
Exotic Smoothness and Physics Differential Topology and Spacetime Models 2007
より
11.2.4 Geometric structures on %manifolds and exotic differential structures

To summarize, we hope to have provided support for the conjecture:
Conjecture: The differential structures on a simply-connected compact, 4-manifold M are determined by the homotopy classes [M, BGl(T)+] and
by the algebraic K-theoy K3(T) where T is the hyperfinite II1 factor C*-algebra.
The classes in K3(T) are given by the geometric structure and/or a codamension-1 foliation of a homology 3-sphere in M determining the Akbulut cork of M.

From the physical point of view, this conjecture is very interesting
because it connects the abstract theory of differential structures with well-known structures in physics like operator algebras or bundle theory.
Perhaps such speculations may provide a geometrization of quantum mechanics or more.
We close this section, and book, which these highly conjectural remarks.