<正> Consider a nonhomogeneous fluid flowing through a homogeneous porous medium occupyinga bounded domain ΩR~n.Let u=u(x,t)represent the density of the fluid
<正> Let M be a smooth, compact (closed and without boundary) surface. Consider the metricsσ(z)|dz|~2 and ρ(ω)|dω|~2 on M, where z=x+iy and ω=u+iv are conf