---
slug: oip-invariant-2-32-least-action-variational-principles
title: Invariant 3.2 — 3.2 Least action / variational principles
canonical: https://miscsubjects.com/a/oip-invariant-2-32-least-action-variational-principles
---

# Invariant: 3.2 Least action / variational principles

### 3.2 Least action / variational principles
Nature extremizes a quantity. **Sources:** Fermat (optics); Maupertuis, Euler, Lagrange, Hamilton; Feynman (path integral). **Domains:** all physics, optics, mechanics; economics (optimization); AI (loss minimization). **Scale:** quantum → cosmic. **Dual:** — (this *is* the economy principle). **Tier:** T0/T1. **Falsifier:** a fundamental law not expressible as an extremum. **Maps:** A₂, A₉.

---

## Corpus map
- Same invariant, other planes: [Catalogue node C02](/a/oip-node-c02-least-action-variational-principles) · [Encyclopedia C02](/a/convergence-encyclopedia-c02)
- Inventory hub: [Convergence Catalogue — Public Article](/a/oip-convergence-public-article)
