Gromov's inequality for complex projective space
In Riemannian geometry, Gromov's optimal stable 2-systolic inequality is the inequality s t s y s 2 n ≤ n ! v o l 2 n ( C P n ) {\displaystyle \mathrm {stsys} _{2}{}^{n}\leq n!
Source: Wikipedia — Gromov's inequality for complex projective space (CC BY-SA 4.0)