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31. Potential Theory

This volume studies harmonic, subharmonic, and superharmonic functions, along with potentials and their applications to analysis, geometry, and...

This volume studies harmonic, subharmonic, and superharmonic functions, along with potentials and their applications to analysis, geometry, and physics. It connects closely with partial differential equations and complex analysis.

Part I. Foundations

Chapter 1. Harmonic Functions

1.1 Definition via Laplace equation 1.2 Mean value property 1.3 Maximum and minimum principles 1.4 Uniqueness results 1.5 Examples

Chapter 2. Subharmonic and Superharmonic Functions

2.1 Definitions 2.2 Basic properties 2.3 Comparison principles 2.4 Upper and lower envelopes 2.5 Examples

Chapter 3. Laplace Equation

3.1 Formulation 3.2 Solutions in ℝⁿ 3.3 Boundary value problems 3.4 Uniqueness and existence 3.5 Examples

Part II. Classical Potential Theory

Chapter 4. Newtonian Potentials

4.1 Fundamental solutions 4.2 Potential functions 4.3 Properties 4.4 Applications 4.5 Examples

Chapter 5. Green’s Functions

5.1 Definition 5.2 Construction 5.3 Boundary conditions 5.4 Applications 5.5 Examples

Chapter 6. Dirichlet Problem

6.1 Formulation 6.2 Existence and uniqueness 6.3 Perron method 6.4 Applications 6.5 Examples

Part III. Energy and Capacity

Chapter 7. Energy Integrals

7.1 Definition 7.2 Properties 7.3 Minimization principles 7.4 Applications 7.5 Examples

Chapter 8. Capacity

8.1 Definition 8.2 Properties 8.3 Relation to measure 8.4 Applications 8.5 Examples

Chapter 9. Equilibrium Measures

9.1 Definition 9.2 Existence and uniqueness 9.3 Properties 9.4 Applications 9.5 Examples

Part IV. Fine Properties

Chapter 10. Fine Topology

10.1 Definition 10.2 Fine continuity 10.3 Thin sets 10.4 Applications 10.5 Examples

Chapter 11. Boundary Behavior

11.1 Regular boundary points 11.2 Fatou-type theorems (overview) 11.3 Limits at boundary 11.4 Applications 11.5 Examples

Chapter 12. Singularities

12.1 Isolated singularities 12.2 Removable singularities 12.3 Classification 12.4 Applications 12.5 Examples

Part V. Probabilistic Connections

Chapter 13. Brownian Motion

13.1 Definition 13.2 Connection to harmonic functions 13.3 Hitting probabilities 13.4 Applications 13.5 Examples

Chapter 14. Stochastic Processes

14.1 Markov processes 14.2 Potential kernels 14.3 Probabilistic representation 14.4 Applications 14.5 Examples

Chapter 15. Dirichlet Forms

15.1 Definitions 15.2 Energy interpretation 15.3 Connections to PDEs 15.4 Applications 15.5 Examples

Part VI. Potential Theory in Complex Analysis

Chapter 16. Logarithmic Potentials

16.1 Definitions 16.2 Properties 16.3 Equilibrium problems 16.4 Applications 16.5 Examples

Chapter 17. Plurisubharmonic Functions (Overview)

17.1 Definitions 17.2 Properties 17.3 Complex potential theory 17.4 Applications 17.5 Examples

Chapter 18. Capacity in Complex Analysis

18.1 Definitions 18.2 Relations to sets 18.3 Applications 18.4 Examples 18.5 Connections

Part VII. Applications

Chapter 19. PDE Applications

19.1 Elliptic equations 19.2 Boundary value problems 19.3 Regularity 19.4 Applications 19.5 Examples

Chapter 20. Geometry Applications

20.1 Minimal surfaces (overview) 20.2 Geometric flows 20.3 Potential methods 20.4 Applications 20.5 Examples

Chapter 21. Physics Applications

21.1 Electrostatics 21.2 Gravitational fields 21.3 Fluid flow 21.4 Applications 21.5 Examples

Part VIII. Research Directions

Chapter 22. Advanced Topics

22.1 Nonlinear potential theory 22.2 Metric space potential theory 22.3 Connections to analysis 22.4 Modern developments 22.5 Emerging areas

Chapter 23. Open Problems

23.1 Boundary regularity 23.2 Capacity estimates 23.3 Nonlinear equations 23.4 Computational challenges 23.5 Future directions

Chapter 24. Historical and Conceptual Notes

24.1 Development of potential theory 24.2 Key contributors 24.3 Evolution of ideas 24.4 Cross-disciplinary impact 24.5 Summary

Appendix

A. Fundamental solutions reference B. Key theorems summary C. Proof techniques checklist D. Example catalog E. Cross-reference to other MSC branches

This volume develops potential theory as the study of harmonic behavior and energy minimization. It connects analysis, probability, and physics through the Laplace equation and related structures.