*Does there exist a pair of smooth manifolds $(M,N),$ $M\ne N$ related by an isometry $g,$ s.t. every smooth regular foliation of $M$ satisfies some differential equation on $N,$ and every smooth regular foliation of $N$ satisfies some differential equation on $M?$*
Essentially one is taking all smooth regular foliations on $M,$ restricting to the metric of $N$ which can be obtained via the isometry $g,$ and checking whether these foliations satisfy differential equations. The same process is done with foliations on $N.$