In this paper,we show that,on the Dirichlet-type space of unit disk,the essential norm of a noncompact Toeplitz operator equals its distance to the set of compact Toeplitz operators,and moreover,this distance is realized by infinitely many compact Toeplit
This paper considers the inverse acoustic wave scattering by a bounded penetra-ble obstacle with a conductive boundary condition.We will show that the penetrabl
Let f be a twice continuously differentiable self-mapping of a unit disk satisfying Poisson differential inequality |△f(z)|≤B·|Df(z)|2 for some B>0 and f(0)=
We prove that, as in the finite dimensional case, the space of Bloch functions on the unit ball of a Hilbert space contains, under very mild conditions, any semi-Banach space of analytic functions invariant under automorphisms. The multipliers for such Bl
The severe acute respiratory syndrome COVID-19 was discovered on Decem-ber 31,2019 in China.Subsequently,many COVID-19 cases were reported in many other countri
In this article,we established the structure of all eigenvalues and the oscillation property of corresponding eigenfunctions for discrete clamped beam equation △4u(k-2)=λm(k)u(k),k∈[2,N+1]Z,u(0)=△u(0)=0=u(N+2)=△u(N+2)with the weight function m:
In this paper,we study the proximal relation,regionally proximal relation and Banach proximal relation of a topological dynamical system for amenable group acti
In the present paper,we have discussed the commutativity of prime rings and extended some well known results concerning derivation and generalized derivations to b-generalized derivations.