13: Formal Properties of Perturbation Theory

The following sections are included:

• Connectedness Structure of Feynman Diagrams

• Functional Differential Equations

• Decomposition of Green Functions into Connected Green Functions

• Functional Differential Equation for W[j[

• Iterative Solution

• Vertex Functions

• The Generating Functional for Vertex Functions

• Functional Differential Equation for Γ[Φ]

• Effective Action as Basis for Variational Calculations

• Effective Potential

• Higher Effective Actions

• High Orders in a Simple Model

• Notes and References