w_{\infty} and sl_q(2) Algebras in the Landau Problem and Chern-Simons   Theory on a Torus
  We discuss $w_\infty$ and $sl_q(2)$ symmetries in Chern-Simons theory and Landau problem on a torus. It is shown that when the coefficient of the Chern-Simons term, or when the total flux passing through the torus is a rational number, there exist in general two $w_\infty$ and two $sl_q(2)$ algebras, instead of one set each discussed in the literature. The general wavefunctions for the Landau problem with rational total flux is also presented. 
Choon-Lin Ho (Dept. of Physics, Tamkang University, Taiwan)