1. Faculty of Mathematics and Computer Science,Freiberg University of Mining and Technology, Bernhard yon Cotta Str. 2, D-09596 Freiberg, Germany 2. Institute of Mathematics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan
Abstract:
This work is concerned with the proof ofLp-Lq decay estimates for solutions of the Cauchy problem forutt−λ2(t)b2(t)Δu=0. The coefficient consists of an increasing smooth function λ and an oscillating smooth and bounded functionb which are uniformly separated from zero. The authors' main interest is devoted to the critical case where one has an interesting interplay between the growing and the oscillating part.