Rationality of inner twisted flags of type $A_n$

Abstract

We prove that $\mathrm{rcodim}(X)\ge 2$ if $X$ is a rational inner twisted flag of type $A_n$.

5 pages, comments are welcome. arXiv admin note: text overlap with arXiv:1607.01043, arXiv:1608.03085, arXiv:1607.04834