Abundance of 3-Planes on Real Projective Hypersurfaces

© 2015, Institute for Mathematical Sciences (IMS), Stony Brook University, NY.We show that a generic real projective n-dimensional hypersurface of odd degree d, such that 4(n-2)=(d+33), contains “many” real 3-planes, namely, in the logarithmic scale their number has the same rate of growth, d3log d, as the number of complex 3-planes. This estimate is based on the interpretation of a suitable signed count of the 3-planes as the Euler number of an appropriate bundle