Implicit Updating of HJB deja-vu de Newton's Method
Interestingly, when using implicit updating to solve a continuous time system (of a certain structure), it coincide with Newton’s Method Setup Consider a household with state $(a, z) \in \mathcal{A} \times \mathcal{Z}$, where $a$ denotes assets and $z$ follows a Poisson process with intensity matrix $\Lambda$. Hamilton-Jacobi-Bellman Equation: $$ \rho v(a,z) = \max_c \left \lbrace u(c) + \partial_a v(a,z) \cdot s(a,z) + \sum_{z'} \lambda_{zz'} v(a,z') \right\rbrace $$where savings $s(a,z) = ra + wz - c(a,z)$. ...