“…The subject of (k, n − k) conjugate boundary value problems have a wide range of applications, for example in material mechanics and physical sciences, such as be used to model the deformation of elastic beams. Recently, many people paid attention to existence result of solution of (k, n − k) conjugate boundary value problems, such as [10,13,18,31,34,36,44]. If n = 4 and k = 2, then the conjugate boundary value problem reduces to the fourth order problem, because it describes the deflection of an elastic beam under a certain force.…”