“…Later, refinements by Hald [17] and Suzuki [34] of Hochstadt and Lieberman's theorem showed that the boundary conditions at x = 1 for L 1 and L 2 need not be assumed a priori to be the same and that if q is continuous, then one only needs λ 1,n = λ 2,m(n) for all values of n but one, that is, one eigenvalue can be missing. However, this is no longer true if the boundary condition at x = 1 is different and q is discontinuous for all values of n but one (see [16]). The same boundary condition for L 1 and L 2 at x = 0, however, is crucial for Hochstadt and Lieberman's theorem to hold (see [33]).…”