Sectorial oscillation theory of linear differential equations

In this paper, the sectorial oscillation of the solutions of higher order homogeneous linear differential equations f(k) + An-2(z)f(k-2) + ⋯ + A1(z)f/ + A0(z)f = 0f(k) + An-2(z)f(k-2) + ⋯ + A1(z)f/ + A0(z)f = 0 with infinite order entire function coefficients is studied. Results are obtained to extend some results in [19] and [18].