In this paper, we investigate the relationship between the solutions, their 1st and 2nd derivatives of some second order linear differential equations and meromorphic function of finite order. We obtain some precise estimates.

In this paper, we consider the nonlinear stability of a boundary layer of the Boltzmann equation with the cutoff hard potential when Mach number at far-field is greater than 1. Based on the Green’s function for the Cauchy problem constructed in M.-Y. Lee, T.-P. Liu and S.-H. Yu and the weighted energy method, we obtain the estimates for the Green’s function of the initial boundary problem and use it to obtain the nonlinear stability with an almost exponential convergent rate to the nonlinear Knudsen layer.

We show that $L^2$ energy estimates combined with Cauchy integral formula for holomorphic functions can provide bounds for higher-order derivatives of smooth solutions of Navier-Stokes equations. We then extend this principle to weak solutions to improve regularization rates obtained by standard energy methods.

We generalize a construction of Dunkl, obtaining a wide class intertwining functions on the symmetric group Sn and a related family of multidimensional Hahn polynomials. Following a suggestion of Vilenkin and Klimyk, we develop a tree-method approach for those intertwining functions. Moreover, using our theory of $S_n$-intertwining functions and James version of the Schur- Weyl duality, we give a proof of the relation between Hahn polynomials and $SU(2)$ Clebsch-Gordan coefficients, previously obtained by Koornwinder and by Nikiforov, Smorodinskiĭ and Suslov in the $SU(2)$-setting. Such relation is also extended to the multidimensional case.

The aim of this paper is to characterize hypoelliptic convolution-equations in $\cal{S}' (\Bbb R)$ for the Dunkl theory on the real line. For this we determine the spaces of convolution and multiplication operators in $\cal{S}' (\Bbb R)$ for the Dunkl convolution and we show that the Fourier-Dunkl transform is a topological isomorphism between them.

In this paper, we introduce an iterative scheme by viscosity approximation method for obtaining a common element of the set of solutions of an equilibrium problem and the set of fixed points of a nonexpansive mapping and the set of solutions of the variational inequality for an inverse-strongly monotone mapping in a Hilbert space. We obtain a strong convergence which improves and extends S. Takahashi and W. Takahashi’s result [S. Takahashi, W. Takahashi, Viscosity approximation methods for equilibrium problems and fixed point problems in Hilbert spaces, J. Math. Anal. Appl. 331 (2007) 506-515].