Electronic Journal of Differential Equations,
Vol. 2007(2007), No. 85, pp. 1-12.

Title: Energy estimate for wave equations with  coefficients in some 
       Besov type class

Author: Shigeo Tarama (Osaka City Univ., Japan)

Abstract:
 In this paper, we obtain an energy estimate for wave equations with
 coefficients satisfying Besov  type  conditions.
 We give an example of a wave equation with  continuous and nowhere
 differentiable  coefficients for which the $L^2$ estimate holds.
  
Submitted February 14, 2007. Published June 6, 2007.
Math Subject Classifications: 35L05, 16D10.
Key Words: Wave equation; energy estimate; non regular coefficients.