Clarke Differentials and the Envelope Theorem in Dynamic Programming
Yuhki Hosoya
TL;DR
This paper extends the envelope theorem to deterministic dynamic programming without requiring differentiability, convexity, or boundedness, by employing the Clarke differential. It develops a self-contained framework of locally Lipschitz functions and Clarke calculus, culminating in a main result that bounds ∂°ĤV(x̄) by the x-derivative of the stage function w via a suitable optimizer ȳ in the policy correspondences. The contribution lies in proving the envelope property under very weak assumptions, enabling application to standard economic models such as CRRA utilities and Cobb–Douglas or AK technologies. The work broadens the scope of envelope-type results to non-smooth settings, with practical implications for sensitivity analysis in deterministic DP models and reduced-form economic applications.
Abstract
In this paper, we consider a deterministic dynamic programming model, and derive the envelope theorem using the Clarke differential. Compared with previous research, we do not require differentiability, convexity, or boundedness.
