On the existence of monotonic fronts for a class of physical problems described by the equation $\lambda u^{\prime \prime \prime }+u^{\prime }=f(u)$

R. D. Benguria, M. C. Depassier

We obtain an upper bound on the value of $\lambda$ for which monotonic front solutions of the equation $\lambda u^{\prime \prime \prime }+u^{\prime }=f(u)$ with $\lambda >0$ may exist.