On a class of Cauchy problems with applications in nonlinear partial differential equations
Feida Jiang, Neil S. Trudinger, Qiao-Qiao Xu
TL;DR
The paper develops a unified ODE framework for a broad Cauchy problem on $(0,+\infty)$ and proves a sharp Keller–Osserman criterion governing the existence of entire solutions. It then applies these results to nonlinear PDEs involving $k$-Hessian and $\Pi_k$-Hessian operators, including degenerate and singular right-hand sides and generalized $p$-Hessian variants, establishing necessary and sufficient KO-type conditions across multiple parameter regimes. A key feature is handling the critical ranges of $\tau$ relative to $q$ and $\theta$, notably the novel $0<\theta<1$ cases and the $p$-generalized Hessian scenarios, thereby yielding a comprehensive set of criteria for entire solvability and subsolution existence in fully nonlinear elliptic equations in $\mathbb{R}^n$. The results provide a robust toolkit for constructing entire subsolutions and understanding global solvability in elliptic PDEs with geometric operators, with duality between $k$-Hessian and $\Pi_k$-Hessian frameworks. These contributions extend classical Keller–Osserman theory to a broad class of nonlinear, potentially degenerate equations, offering implications for geometric problems and nonlinear PDE modeling.
Abstract
In this paper, we investigate the existence and nonexistence of entire solutions to a general class of Cauchy problems in the positive half line. Our results provide a unified approach to proving sharp local and entire solvability of nonlinear partial differential equations in n-dimensional Euclidean space. As applications of the general framework, we present such results for two series of nonlinear equations: a series of k-Hessian type equations and a new series of P-k-Hessian type equations. These results are also proved for the more general p-Hessian matrices, with p > 1, and degenerate non homogeneous terms.
