LATTICES AND PERIODIC GEODESICS IN PSEUDORIEMANNIAN 2-STEP NILPOTENT LIE GROUPS
LATTICES AND PERIODIC GEODESICS IN PSEUDORIEMANNIAN 2-STEP NILPOTENT LIE GROUPS
We give a basic treatment of lattices $\Gamma$ in these groups. Certain tori $T_F$ and $T_B$ provide the model fiber and the base for a submersion of $\Gamma\backslash N$. This submersion may not be pseudoriemannian in the usual sense, because the tori may be degenerate. We then begin the study …