Behavior as $t\rightarrow \infty$ of Solutions of a problem in   Mathematical Physics
  A class of solutions, decaying as $t\rightarrow \infty$, of a two-dimensional model problem on the oscillations of an ideal rotating fluid in some domains with angular points is constructed explicitly. The existence of solutions whose $L_2$-norms decrease more rapidly than any negative power of $t$, is established. 
Saule D. Troitskaya
math-ph math.MP