  Let A be an n by m matrix with real entries. Consider the set Bad_A of x \in
[0,1)^n for which there exists a constant c(x)>0 such that for any q \in Z^m
the distance between x and the point {Aq} is at least c(x) |q|^{-m/n}. It is
shown that the intersection of Bad_A with any suitably regular fractal set is
of maximal Hausdorff dimension. The linear form systems investigated in this
paper are natural extensions of irrational rotations of the circle. Even in the
latter one-dimensional case, the results obtained are new.

Number Theory;Dynamical Systems