“…There is a wealth of results in this direction, see, e.g., [1,3,17,20,21,24,25,29,30,32]. In many of these papers the equation studied is u"(t,x) = tj)(ux(t,x))x+ / a(t-s)y/(ux(s,x))xds + g(t,x), which is the same as (1) if </> = y/ = o, k(0) = 1, and a = k'.…”