Static class-guided selection of elementary solutions in non-monotone vanishing discount problems
Panrui Ni, Jun Yan, Maxime Zavidovique
TL;DR
The paper analyzes a non-monotone vanishing discount problem for Hamilton–Jacobi equations on a closed manifold by introducing a generalized discount term with a signed coefficient $a(x)$. By choosing $a(x)>0$ on a selected static class and $a(x)<0$ elsewhere, it proves that the maximal discounted solution $u_\lambda$ converges uniformly to an elementary solution of the critical equation, represented as $h^\infty(x_0,x)+C$ with $x_0$ in the chosen static class and $C$ determined by a Mather-measure-based infimum. Importantly, by varying the sign pattern of $a$ across the finite static classes, all elementary solutions can be recovered as limits, revealing a purely dynamical mechanism for selection beyond monotonicity. The analysis connects vanishing discount limits with large-time behavior, leveraging the Peierls barrier $h^\infty$, static-class partitions, and Mather measures to characterize the limit. This provides a principled method to select multiple critical solutions in non-monotone settings, extending weak KAM/Mather theory to a broader class of discounted Hamilton–Jacobi problems.
Abstract
We study a generalized vanishing discount problem for Hamilton--Jacobi equations, removing the standard monotonicity assumption, either in a global sense or when integrated against all Mather measures. Specifically, we consider \[ λa(x)u(x)+H(x,Du(x))-Aλ=c_0, \] with a suitably chosen constant $A>0$. By appropriately changing the signs of the function $a(x)$ on different static classes associated with $H$, we show that the maximal viscosity solution converges uniformly as $λ\to 0^+$ and that all elementary solutions of the stationary equation \[ H(x,Du(x))=c_0 \] can be selected as limits. This provides the first result for selecting multiple viscosity solutions in vanishing discount problems beyond the usual monotonicity and integral assumptions, as long as $a(x)$ is positive on one static class. Our results highlight the crucial role of static classes in controlling the asymptotic behavior of viscosity solutions. Previously, under usual monotonicity assumptions, only a single solution could be selected (as discussed in \cite{GL}), whereas our approach allows controlled selection of multiple solutions via static class-guided discount coefficients.
