The Largest Proper Variety of Lattice Ordered Groups
W. Charles Holland · Proceedings of the American Mathematical Society · 1976
If a lattice ordered group $G$ satisfies any identical relation, other than those satisfied by every lattice ordered group, then $G$ is normal valued, and hence satisfies the relation $ab \leqslant {b^2}{a^2}$ for all $a,b \geqslant e$.