مشخصات پژوهش

The purpose of this paper is to develop a theory of best simultaneous approximation to "-simultaneous approximation. We shall introduce the concept of "-simultaneous pseudo Chebyshev, "-simultaneous quasi Chebyshev and "-simultaneous weakly Chebyshev subspaces of a Banach space. Then, it will be determined under what conditions these subspaces are transmitted to and from quotient spaces.