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Aerodynamics of flying saucers. (arXiv:1810.04855v1 [math.DG])
来源于:arXiv
We identify various structures on the configuration space C of a flying
saucer, moving in a three-dimensional smooth manifold M. Always C is a
five-dimensional contact manifold. If M has a projective structure, then C is
its twistor space and is equipped with an almost contact Legendrean structure.
Instead, if M has a conformal structure, then the saucer moves according to a
CR structure on C. With yet another structure on M, the contact distribution in
C is equipped with a cone over a twisted cubic. This defines a certain type of
Cartan geometry on C (more specifically, a type of `parabolic geometry') and we
provide examples when this geometry is `flat,' meaning that its symmetries
comprise the split form of the exceptional Lie algebra G2. 查看全文>>