supported by the“China Natural Science Fund under grant 11871181”;the“China Natural Science Fund under grant 11561053”。
In this paper,we prove that if X is an almost convex and 2-strictly convex space,linear operator T:X→Y is bounded,N(T)is an approximative compact Chebyshev subspace of X and R(T)is a 3-Chebyshev hyperplane,then there...