Mostly nonuniformly sectional expanding systems

Abstract: In this note, we introduce the notion of mostly nonuniform sectional expanding (MNUSE) for singular flows which contains the well known sectional hyperbolicity as well new definitions as asymptotically sectional and multisingular hyperbolicities. We exhibit an example of nonuniformly sectional hyperbolic set, in this new sense, which is neither $2$-sectional hyperbolic nor asymptotically sectional hyperbolic, proving that this is a broader notion of weak hyperbolicity for singular flows. Moreover, in $C^2$ setting, under some assumptions of either the dimension or the sign of Lyapunov exponents of the central subbundle, we prove that attracting MNUSE sets support a physical/SRB measure. And this measure is unique for MNUSE attractors.