Pointwise equidistribution for one parameter diagonalizable group action on homogeneous space

Abstract:

Let $\Gamma$ be a lattice of a semisimple Lie group $L$. Suppose that a one parameter $\operatorname {Ad}$-diagonalizable subgroup $\{g_t\}$ of $L$ acts ergodically on $L/\Gamma$ with respect to the probability Haar measure $\mu$. For certain proper subgroup $U$ of the unstable horospherical subgroup of $\{g_t\}$ and certain $x\in L/\Gamma$ we show that for almost every $u\in U$ the trajectory $\{g_tux: 0\le t\le T\}$ is equidistributed with respect to $\mu$ as $T\to \infty$.