Higher regularity estimates for solutions to $\infty$-Laplacian-type models
João Vitor da Silva, Makson S. Santos, Mayra Soares
TL;DR
The paper addresses higher regularity for inhomogeneous $\Delta_{\infty}$-Laplacian models at interior critical points. It develops a blow-up/renormalization framework in a one-phase tangential regime together with smallness assumptions on the forcing to derive a pointwise decay $|u(x)| \le C\,|x-x_0|^{\alpha}$ with $\alpha = \dfrac{4-\kappa}{3-(m+\kappa)}>1$ at $x_0$ in the $1$-nullity set $C_{\mathcal{Z}}(u)$, plus $C^{[\alpha],\alpha-[\alpha]}$ regularity under additional tangential structure. The work also develops reflecting estimates between the positive and negative parts and a non-degeneracy result under a natural forcing lower bound, with extensions to $(3-\gamma)$-homogeneous operators and Hénon-type variants. Overall, these results advance interior regularity theory for inhomogeneous infinity-Laplacian equations, with implications for obstacle-type, free-boundary, and dead-core problems.
Abstract
In this work, we tackle the higher regularity estimates of solutions to inhomogeneous $\infty-$Laplacian equations at interior critical points. Our estimates provide smoothness properties better than the corresponding available regularity for the model with bounded forcing terms. We explore several scenarios, thereby obtaining improved regularity estimates, which depend on the universal parameters of the model. Our findings connect with nowadays well-known estimates developed for obstacle and dead-core type problems.
