Abstract:
In this paper, we consider the anisotropic Lorentz space of $2\pi$-periodic functions of many variables and the Nikolsky–Besov class in this space. We obtain estimates for the best approximations along the hyperbolic cross and the best $M$-term approximations of functions of the Nikolsky—Besov class with respect to the norm of the anisotropic Lorentz space for various relations between the parameters of the class and the space.
Keywords:Lorentz space, trigonometric polynomial, best $M$-term approximation