La conjecture des immersions
Line Bundles and Harmonic Analysis on Compact Groups.
Line Bundles over Framed Manifolds.
Line bundles with
We prove that on a -complex the obstruction for a line bundle to be the fractional power of a suitable pullback of the Hopf bundle on a 2-dimensional sphere is the vanishing of the square of the first Chern class of . On the other hand we show that if one looks at integral powers then further secondary obstructions exist.