Abstract :
Let p>1, α 0, and L∞(R)∩L1(R) change its sign finite times. This paper is concerned with a Cauchy problem [formula] Define the set of zeros of a solution u by Z(t)={x R : u(x, t)=0} for t>0. In the case of α=0, we show that the set Z(t) is contained in [−Ct, Ct] for large t>0 with some C>0 and that this order of t is best possible. When α>0, we also give estimates of Z(t) for global solutions and prove that Z(t) [−K, K] for all t (0, T) with some K>0 for each blowup solution, where T is the blowup time.
