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On the existence of degenerate hypersurfaces in Sasakian manifolds. (English) Zbl 0977.53056
In [Int. J. Math. Math. Sci. 16, 545-556 (1993; Zbl 0787.53048)] A. Bejancu and K. L. Duggal introduced indefinite Sasakian structures (f,ξ,η,g) and constructed a special example of index s on 2n+1 . In the paper under review the author is concerned with hypersurfaces M of the latter space, which are tangent to the structure vector field ξ. He shows: If s=n then M always is non-degenerate, but for s=1 degenerate examples exist.
MSC:
53C40Global submanifolds (differential geometry)
53C25Special Riemannian manifolds (Einstein, Sasakian, etc.)