Transversality and separation of zeros in second order differential equations
Robert Laister, Robert Beardmore · Proceedings of the American Mathematical Society · 2002
Sufficient conditions on the non-linearity $f$ are given which ensure that non-trivial solutions of second order differential equations of the form $Lu=f(t,u)$ have a finite number of transverse zeros in a given finite time interval. We also obtain a priori lower bounds on the separation of zeros of solutions. In particular our results apply to non-Lipschitz non-linearities. Applications to non-linear porous medium equations are considered, yielding information on the existence and strict positivity of equilibrium solutions in some important classes of equations.