This article makes use of variable gradient method and structure Lyapunov Function to solve a kind of global asymptotic stability for solutions of non-linear system of the second order.

Because the gradient vectors here are f sub x, z If you have a third variable z gz then you have also an equation f sub z equals lambda g sub z.

This paper presents an expression for temperature distribution in growing crystal by considering the ambient temperature gradient as a variable introduced in LEC model.