A note on sub-orthogonal lattices
  It is shown that, given any $k$-dimensional lattice $\Lambda$, there is a lattice sequence $\Lambda_w$, $w\in \mathbb Z$, with sub-orthogonal lattice $\Lambda_o \subset \Lambda$, converging to $\Lambda$ (unless equivalence), also we discuss the conditions for faster convergence. 
Jo\~ao Eloir Strapasson
cs.IT math.IT