“…Moreover, the semigroup e tA can be extended to L p (0, 1) (p > 1), (1.1) e tA x L p ≤ e γpt |x| L p , x∈ L p (0, 1), where γ p = 2p −1 (p−1)π 2 . Note that the usual Sobolev space W k,p (0, 1) can be extended to W s,p (0, 1), for s ∈ R, then by [18], e tA (t ≥ 0) have the smoothing properties: for any s 1 , s 2 ∈ R with s 1 ≤ s 2 , r ≥ 1, e tA : W s1,r (0, 1) → W s2,r (0, 1) and there exists a constant C 1 depending on s 1 , s 2 , r such that (1.2) e tA z W s 2 ,r (0,1) ≤ C 1 1 + t (s1−s2)/2 |z| W s 1 ,r (0,1) , z ∈ W s1,r (0, 1).…”