Let$M$ be a Complete simplyconnected ndimensional Riemannian manifold with nonpositive curvature,$\Omega $
is a open subset of $M$ ,If $n\geq 4$
Is anyone give a estimate of $\frac{Vol_{n}\left ( \Omega \right )}{Vol_{n1}\left ( \Omega \right )^{\frac{n}{n1}}}$ ?,If $\Omega $
replace by $B^{n}\left ( 1 \right )$ `,it is a unit sphere,,estimate?



It is an old open problem.


