Time-reversal in hyperbolic s. p. d. e. 's (Q1872257)

The authors consider two types of changes of variables in a class of hyperbolic s.p.d.e.'s. Time-reversals for the Brownian sheet and for equations with constant coefficients are discussed in detail. A necessary and sufficient condition for the reversal in two coordinates to satisfy an s.p.d.e. with local coefficients is proved. This result yields a negative conclusion concerning the reversal in time of the solution to the stochastic wave equation (in one spatial dimension) driven by white noise.