%0 Journal Article %T Frobenius morphism and semi-stable bundles %A Xiaotao Sun %J Mathematics %D 2009 %I arXiv %X This article is the expanded version of a talk given at the conference: Algebraic geometry in East Asia 2008, Seoul. In this notes, I intend to give a brief survey of results on the behavior of semi-stable bundles under the Frobenius pullback and direct images. Some results are new. %U http://arxiv.org/abs/0904.1560v1