Mathematics Branches, Topics, and Sub-Topics

A structured visual guide to the major mathematical areas and their relationships.

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49Nxx Geometry and constraints

This subtopic introduces the core ideas in geometry and constraints, including foundational concepts, standard methods, and the main questions used to organize the area. Typical uses include building mathematical background, framing related research problems, and supporting applications in neighboring fields where these concepts provide useful structure.

Specific topics

49N05 Linear optimal control problems

Overview

Linear optimal control problems exploit linear dynamics and convex costs to obtain tractable theory and efficient computational methods.

Related Wikipedia Page

Wikipedia: Linear-quadratic regulator

Useful Links

Key Ideas

  • linear dynamics
  • convex cost
  • feedback laws

Typical Uses

Central in engineering control design.

Applications

  • Aerospace control
  • Process control
  • Robotics

References

Recommended Textbooks

49N10 Linear-quadratic optimal control problems

Overview

The linear-quadratic framework gives closed-form solutions for many optimal control problems and acts as a benchmark for more general theory.

Related Wikipedia Page

Wikipedia: Linear-quadratic regulator

Useful Links

Key Ideas

  • Riccati equations
  • quadratic cost
  • feedback gains

Typical Uses

Widely used in aerospace, robotics, and process control.

Applications

  • Satellite attitude control
  • Vehicle stabilization
  • Supply chains

References

Recommended Textbooks

49N15 Duality theory in mathematical programming

Overview

Duality theory relates a primal optimization problem to a related dual problem and gives powerful certificates of optimality and sensitivity.

Related Wikipedia Page

Wikipedia: Duality (optimization)

Useful Links

Key Ideas

  • primal-dual relationships
  • weak and strong duality
  • sensitivity

Typical Uses

Used in economics, operations research, and convex analysis.

Applications

  • Network optimization
  • Pricing
  • Resource allocation

References

Recommended Textbooks

49N20 Periodic optimal control problems

Overview

This topic studies control problems with periodic objectives, constraints, or state trajectories, where periodicity imposes special structure.

Related Wikipedia Page

Wikipedia: Periodic orbit

Useful Links

Key Ideas

  • periodic trajectories
  • Floquet theory
  • cyclic optimization

Typical Uses

Relevant in cyclic processes and repetitive control tasks.

Applications

  • Energy management
  • Manufacturing cycles
  • Biological rhythms

References

Recommended Textbooks

49N25 Impulsive optimal control problems

Overview

Impulsive control problems allow instantaneous changes in the state, making them suitable for models with jumps or abrupt interventions.

Related Wikipedia Page

Impulsive control (Wikipedia)

Useful Links

Key Ideas

  • jump dynamics
  • impulse controls
  • hybrid systems

Typical Uses

Applied when decisions happen in discrete bursts rather than continuously.

Applications

  • Finance
  • Epidemiology
  • Hybrid systems

References

Recommended Textbooks

49N30 Problems with incomplete information, min-max optimization, robust control

Overview

This area studies decision problems where information is incomplete or uncertain, and the objective is to perform well under worst-case scenarios.

Related Wikipedia Page

Wikipedia: Robust control

Useful Links

Key Ideas

  • min-max formulations
  • robustness
  • uncertainty sets

Typical Uses

Standard in systems engineering and decision theory under uncertainty.

Applications

  • Robotics
  • Power systems
  • Finance

References

Recommended Textbooks

49N35 Optimal feedback synthesis

Overview

Optimal feedback synthesis seeks control laws that depend on the current state and implement the optimal policy dynamically.

Related Wikipedia Page

Wikipedia: Feedback

Useful Links

Key Ideas

  • feedback laws
  • Hamilton-Jacobi-Bellman equations
  • stabilization

Typical Uses

Central in control engineering and robotics.

Applications

  • Autonomous vehicles
  • Process control
  • Aerospace guidance

References

Recommended Textbooks

49N45 Inverse problems in optimal control

Overview

Inverse problems in optimal control seek to recover unknown parameters, costs, or constraints from observed behavior or measurements.

Related Wikipedia Page

Wikipedia: Inverse problem

Useful Links

Key Ideas

  • parameter identification
  • regularization
  • data assimilation

Typical Uses

Used in systems biology, geophysics, and engineering diagnostics.

Applications

  • Medical imaging
  • Geophysics
  • Parameter estimation

References

Recommended Textbooks

49N60 Regularity of solutions/controls

Overview

Regularity theory studies smoothness and structural properties of optimal controls and their associated states or value functions.

Related Wikipedia Page

Wikipedia: Regularity theory

Useful Links

Key Ideas

  • smoothness
  • boundary regularity
  • Sobolev regularity

Typical Uses

Important for numerical approximation and qualitative analysis.

Applications

  • PDE control
  • Free-boundary problems
  • Mechanics

References

Recommended Textbooks

49N70 Differential games and control

Overview

Differential games model interactions among multiple agents, each pursuing their own objective under dynamic constraints.

Related Wikipedia Page

Wikipedia: Differential game

Useful Links

Key Ideas

  • Nash equilibria
  • feedback strategies
  • value functions

Typical Uses

Used in economics, robotics, and pursuit-evasion problems.

Applications

  • Pursuit-evasion
  • Defense problems
  • Market competition

References

Recommended Textbooks

49N75 Pursuit and evasion games

Overview

Pursuit-evasion problems study how one or more pursuers can catch an evader while both respond dynamically.

Related Wikipedia Page

Wikipedia: Pursuit-evasion

Useful Links

Key Ideas

  • capture conditions
  • state constraints
  • strategic interaction

Typical Uses

Relevant to surveillance, robotics, and security.

Applications

  • Search-and-rescue
  • Robotics
  • Defense

References

Recommended Textbooks

49N80 Mean field games and control

Overview

Mean field methods approximate large-population interactions by a continuum of agents and study equilibria and optimization in that limit.

Related Wikipedia Page

Wikipedia: Mean field game theory

Useful Links

Key Ideas

  • mean field equilibria
  • coupled PDE systems
  • population limits

Typical Uses

Used in economics, traffic modeling, and swarm control.

Applications

  • Traffic flow
  • Crowd dynamics
  • Finance

References

Recommended Textbooks

49N90 Applications of optimal control and differential games

Overview

This topic studies how the theory of optimal control and differential games is applied to real-world systems across engineering, economics, and biology.

Related Wikipedia Page

Wikipedia: Optimal control

Useful Links

Key Ideas

  • application-driven modeling
  • interdisciplinary methods
  • implementation challenges

Typical Uses

Useful as a bridge between theory and practice in many applied domains.

Applications

  • Biological control
  • Energy systems
  • Transportation

References

Recommended Textbooks