We give a new Hilbert-type integral inequality with the best constant factor by estimating the weight function. And the equivalent form is considered.

By means of weight functions and Hermite-Hadamard's inequality, and introducing a discrete interval variable, a more accurate half-discrete Hardy-Hilbert-type inequality related to the kernel of arc tangent function and a best possible constant factor is given, which is an extension of a published result. The equivalent forms and the operator expressions are also considered.

Let X be a Hilbert-space valued martingale and Y a real-valued supermartingale which are orthogonal and with Y diierentially subordinate to X. Then where the constant (2) is Catalan's constant whose approximate value is 0:915965594. The constant K is B. Davis' constant in the Kolmogorov's weak-type inequality for conjugate harmonic functions in the unit disk. The inequality is sharp.

Some reverses of the continuous triangle inequality for Bochner integral of vectorvalued functions in Hilbert spaces are given. Applications for complex-valued functions are provided as well.

In this paper, by using the way of weight function and real analysis techniques, a new integral inequality with some parameters and a best constant factor is given, which is a relation to Hilbert’s integral inequality and some base Hilbert-type integral inequalities. The equivalent form and the reverse forms are considered.

In this paper we introduce operator preinvex functions and establish a Hermite–Hadamard type inequality for such functions. We give an estimate of the right hand side of a Hermite–Hadamard type inequality in which some operator preinvex functions of selfadjoint operators in Hilbert spaces are involved. Also some Hermite–Hadamard type inequalities for the product of two operator preinvex functio...

* Correspondence: limin-zou@163. com School of Mathematics and Statistics, Chongqing Three Gorges University, Chongqing 404100, People’s Republic of China Abstract We obtain an improved Heinz inequality for scalars and we use it to establish an inequality for the Hilbert-Schmidt norm of matrices, which is a refinement of a result due to Kittaneh. Mathematical Subject Classification 2010: 26D07;...

where φ : A → B(H) is a unital completely positive linear map from a C-algebra A to linear operators on a Hilbert space H, and x is a self-adjoint element in A with spectrum in I. Subsequently M. D. Choi [3] noted that it is enough to assume that φ is unital and positive. In fact, the restriction of φ to the commutative C-algebra generated by x is automatically completely positive by a theorem ...

In this paper we consider the order-like relation for self-adjoint operators on some Hilbert space. This relation is defined by using Jensen inequality. We will show that under some assumptions this relation is antisymmetric.