H Wang, Y He, S Li - Electronic Journal of Differential Equations, 2015 - emis.de
Let α:[0,∞)→(0,∞) be a twice continuous differentiable function which satisfies that α (0)= 1,
α is monotone and 0< c1≤ α (t)≤ c2< 1 for some constants c1, c2. The exact controllability …