<正> In this paper,we improve LaSalle's invariance theorem based on Li'swork(Li Yong,Asymptotic stability and ultimate boundedness,Northeast.Math.J.,6(1
Let U be a weakly closed nest algebra module acting on a Hilbert space H.Given two operators X and Y in B(H),a necessary and sufficient condition for the existe
Some sufficient conditions for the F-Sobolev inequality for symmetric forms are presented in terms of new Cheeger's constants. Meanwhile, an estimate of the