Real four-dimensional biquadrics

V. A. Krasnov

Izvestiya. Mathematics , Tome 75 (2011) no. 2, pp. 371-394.

Résumé

We consider intersections of two real five-dimensional quadrics, which are referred to for brevity as real four-dimensional biquadrics. Their rigid isotopy classes were described long ago: there are 16 such classes. We prove that the rigid isotopy class of a non-singular real four-dimensional biquadric is uniquely determined by the topological type of its real part. To do this, we calculate the dimensions of the cohomology spaces of the real part of a four-dimensional biquadric.

Détail

Keywords: rigid isotopy classes, coarse isotopy classes, index function.
Mots-clés : biquadrics

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