equation icon  N (t,y) = n(y), (336) A(t,y) = a(t)n(y), (337) ( r ) n(y) = cosh my - 1 + -0- sinh m|y|, (338) c a(t) = a0 expH0(t - t0), (339) 2 k2 ( r0) H 0 = ---r0 1 + --- , (340) 3 2c