On the Growth of Solutions of a Class of Higher Order Linear Differential Equations with Extremal Coefficients

We consider that the linear differential equations , where , are entire functions. Assume that there exists , such that is extremal for Yang's inequality; then we will give some conditions on other coefficients which can guarantee that every solution of the equation is of infinite order. More specifically, we estimate the lower bound of hyperorder of if every solution of the equation is of infinite order.