Semi-Explicit Solution of Some Discrete-Time Higher-Order-Cost Mean-Field-Type Control
Julian Barreiro-Gomez, Tyrone E. Duncan, Bozenna Pasik-Duncan, Hamidou Tembine
TL;DR
This paper addresses discrete-time mean-field-type optimal control with higher-order, power-law costs, moving beyond traditional quadratic formulations. It introduces a convex-completion-based framework that yields semi-explicit control laws, cost-to-go coefficients, and backward recursions for a broad class of even-order costs $x^{2p}$ and $u^{2p}$ under deterministic, additive-noise, multiplicative-noise, and mean-field settings. Key contributions include variance-aware extensions, multiplicative-noise handling, and a verification method in the space of measures, with rigorous positivity conditions ensuring well-posed solutions. The approach reveals that higher-order costs tend to produce less aggressive controls than quadratic costs, and numerical experiments illustrate the framework's applicability to water, energy, agriculture, and financial-network contexts. Overall, the work broadens solvable mean-field-type control problems to non-linear, risk-sensitive objectives with semi-explicit, tractable solutions.
Abstract
Traditional solvable optimal control theory predominantly focuses on quadratic costs due to their analytical tractability, yet they often fail to capture critical non-linearities inherent in real-world systems including water, energy, agriculture, and financial networks. Here, we present a unified framework for solving discrete-time optimal control with higher-order state and control costs of power-law form. By building convex-completion techniques, we derive semi-explicit expressions for control laws, cost-to-go functions, and recursive coefficient dynamics across deterministic and stochastic system settings. Key contributions include variance-aware solutions under additive and multiplicative noise, extensions to mean-field-type-dependent dynamics, and conditions that ensure the positivity of recursive coefficients. In particular, we establish that higher-order costs induce less aggressive control policies compared to quadratic formulations, a finding that is validated through numerical analyses.
