By introducing independent parameters and applying the weight coefficients, we use Hermite-Hadamard's inequality and give a more accurate Hardy-Hilbert's inequality in the whole plane with a best possible constant factor. Furthermore, the equivalent forms, a few particular cases and the operator expressions are considered.

In this work, some Hardy-Hilbert’s integral inequalities with the best possible constants are proved. Also, some finite and infinite decompositions of some type Hardy-Hilbert’s integral operators are given. Indeed, for a non-negative kernel K, two Kernels K1 and K2 are given such that TK = TK1 + TK2 and TK = TK1  + TK2  and also, Tk1 = cTk2 for every constant c. So, the space of bounded linear operators is not strictly convex. Also, as an application of infinite decomposition of some Hardy-Hilbert’s integral operators, the convergence of some series of hypergeometric functions are given.

In this work, using semidefinite matrices gives a new generalization of the $l_p$ spaces and some inequalities containing lower bounds of some operators are proved. Also, by defining an inner product on the classes of an equivalence relation on operators, some inequalities similar to the well-known inequalities including the Copson, Cesaro, Hilbert and Hardy inequalities are obtained.

By the method of weight coefficients, techniques of real analysis and Hermite-Hadamard's inequality, a half-discrete Hardy-Hilbert-type inequality related to the kernel of the hyperbolic cosecant function with the best possible constant factor expressed in terms of the extended Riemann-zeta function is proved. The more accurate equivalent forms, the operator expressions with the norm, the reverses and some particular cases are also considered.

In this paper, by the use of the weight coefficients, the transfer formula and the technique of real analysis, an extended multidimensional Hardy-Hilbert-type inequality with a general homogeneous kernel and a best possible constant factor is given. Moreover, the equivalent forms, the operator expressions and a few examples are considered.

In this paper, weakly supercyclicity and weakly hypercyclicity of composition operators on some Hilbert spaces of analytic functions, especially on some weighted Hardy spaces are investigated.

Some Hilbert $C^*$-module versions of H$\ddot{o}$lder-McCarthy and H$\ddot{o}$lder type inequalities and their complementary on a Hilbert $C^*$-module are obtained by Seo \cite{seo-2014}. The purpose of this paper is to extend these results for some operator convex (resp. concave) functions on a Hilbert $C^*$-module via the operator perspective approach. By choosing some elementary functions, we reach some new types of inequalities in Hilbert $C^*$-modules.

In 1964, Levinson [4] proved integral inequalities concerning generalization of Hardy’s inequalities. In this paper two results are given. First one is extension of the Levinson Integral inequalities via convexity and the second is for the Levinson Integral inequalities of Hardy, this inequalities are established for p < 1 and some related inequalities are also considered with a sharp constant.

We introduce variational inequality problems on Hilbert $C^*$-modules and we prove several existence results for variational inequalities defined on closed convex sets. Then relation between variational inequalities, $C^*$-valued metric projection and fixed point theory on Hilbert $C^*$-modules is studied.

In this paper, two pairs of new inequalities are given, which decompose two Hilbert-type inequalities.