%0 Journal Article %T The set of fixed points of a unipotent group %A Zbigniew Jelonek %A Micha£¿ Laso¨½ %J Mathematics %D 2014 %I arXiv %R 10.1016/j.jalgebra.2009.06.007 %X Let $K$ be an algebraically closed field. Let $G$ be a non-trivial connected unipotent group, which acts effectively on an affine variety $X.$ Then every non-empty component $R$ of the set of fixed points of $G$ is a $K$-uniruled variety, i.e, there exists an affine cylinder $W\times K$ and a dominant, generically-finite polynomial mapping $\phi:W\times K\rightarrow R.$ We show also that if an arbitrary infinite algebraic group $G$ acts effectively on $K^n$ and the set of fixed points contains a hypersurface $H$, then this hypersurface is $K$-uniruled. %U http://arxiv.org/abs/1411.5650v1