23/03/22 16:10:00.77 VqclUbtx.net
>>666 被った、貼り直し
>>665
つづき
In the case of one complex variable, the Riemann
mapping theorem says that any simply connected
domain is either C or equivalent to the unit disc. In
contrast, Henri Poincare [17] showed that in higher
dimensions even the ball and the bidisc are not
equivalent, which implies that their boundaries
cannot be equivalent.
In the same article Poincare posed the local
equivalence problem, i.e., to decide when two hypersurfaces are equivalent in the neighbourhoods
of given points. He sketched a heuristic argument
that any two real hypersurfaces in C2 cannot be
expected to be locally equivalent.
In order to solve this equivalence problem
for real hypersurfaces in C2, Elie Cartan [6], [7]
constructed in 1932 a “hypersp