A Note on Multivariate Lyapunov-type Inequality

We transfer the recent obtained result of univariate Lyapunov-type inequality for third order differential equations to the multivariate setting of a shell via the polar method. Our result is better than the result of Anastassiou [Appl. Math. Letters, 24 insert ignore into journalissuearticles values(2011);, 2167-2171] for third order partial differential equations.