Let π : E → B be a fiber bundle with fiber having the mod-2 cohomology algebra of a real or a complex projective space and let π ′ : E ′ → B be vector bundle such that Z2 acts fiber preserving and freely on E and E ′ − 0, where 0 stands for the zero section of the bundle π ′ : E ′ → B. For a fiber preserving Z2-equivariant map f : E → E ′ , we estimate the cohomological dimension of the zero se...

This paper is a study of Glasner’s definition of quasi-factors in the setting of infinite-measure preserving system. The existence of a system with zero Krengel entropy and a quasi-factor with positive entropy is obtained. On the other hand, relative zero-entropy for conservative systems implies relative zero-entropy of any quasi-factor with respect to its natural projection onto the factor. Th...

We show that the integrated Lyapunov exponents of C volume preserving diffeomorphisms are simultaneously continuous at a given diffeomorphism only if the corresponding Oseledets splitting is trivial (all Lyapunov exponents equal to zero) or else dominated (uniform hyperbolicity in the projective bundle) almost everywhere. We deduce a sharp dichotomy for generic volume preserving diffeomorphisms...