It is shown that if the wave velocity in the telegraph equation is made timehyphen;dependent simple solutions of the diffusion problem are allowed:c=lgr;minus;n/1minus;agr;(r/lgr;)2)mminus;1forndimensions, where lgr;=lgr;(t) andm=(agr;minus;1minus;n)/2. The coefficient agr; is a measure of deviation from classical behavior and determines the position of the boundary; agr;thinsp;rarr;thinsp;0 gives the usual exponential. Factors determining agr; are considered. With increasing agr; there are discontinuous changes leading to lsquo;lsquo;hardrsquo;rsquo; boundaries, which could possibly occur in a system that was sufficiently confined initially. (AIP)
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