Mathematics Branches, Topics, and Sub-Topics

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

Search by code, branch, topic, subtopic, or a keyword from the descriptions.

51Fxx Metric geometry

This subtopic introduces the core ideas in metric geometry, 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

51F05 Absolute planes

Overview

Absolute planes form a foundational setting for metric geometry in which incidence and congruence are treated axiomatically.

Related Wikipedia Page

Wikipedia: Absolute geometry

Useful Links

Key Ideas

  • absolute axioms
  • incidence and congruence
  • parallelism

Typical Uses

Used to understand which geometric facts are independent of the Euclidean parallel postulate.

Applications

  • Non-Euclidean geometry
  • Foundations of geometry
  • Axiomatic geometry

References

Recommended Textbooks

51F10 Absolute spaces

Overview

Absolute spaces generalize plane geometry to higher-dimensional settings while preserving the basic metric and incidence structure.

Related Wikipedia Page

Wikipedia: Metric geometry

Useful Links

Key Ideas

  • metric axioms
  • space of points
  • congruence

Typical Uses

Useful for studying the common features of Euclidean, hyperbolic, and elliptic geometries.

Applications

  • Geometry foundations
  • Distance geometry
  • Synthetic geometry

References

Recommended Textbooks

51F15 Reflection groups, reflection geometries

Overview

Reflection groups provide a powerful symmetry language for metric and synthetic geometry, especially through Coxeter systems.

Related Wikipedia Page

Wikipedia: Reflection group

Useful Links

Key Ideas

  • Coxeter groups
  • mirrors
  • fundamental chambers

Typical Uses

Central in the study of symmetry groups, root systems, and tessellations.

Applications

  • Lie theory
  • Tiling theory
  • Group actions

References

Recommended Textbooks

51F20 Congruence and orthogonality in metric geometry

Overview

Congruence and orthogonality are the metric analogues of incidence and perpendicularity, giving the basic language of geometric comparison.

Related Wikipedia Page

Wikipedia: Orthogonality

Useful Links

Key Ideas

  • distance-preserving maps
  • orthogonality
  • perpendicularity

Typical Uses

Essential for the transition from incidence geometry to analytic or metric geometry.

Applications

  • Euclidean geometry
  • Optimization
  • Molecular geometry

References

Recommended Textbooks

51F25 Orthogonal and unitary groups in metric geometry

Overview

Orthogonal and unitary groups capture the symmetries of inner-product spaces and are central to metric geometry.

Related Wikipedia Page

Wikipedia: Orthogonal group

Useful Links

Key Ideas

  • isometries
  • inner products
  • unitary transformations

Typical Uses

Used in geometry, physics, and signal processing through coordinate-free symmetry analysis.

Applications

  • Quantum mechanics
  • Signal analysis
  • Symmetry groups

References

Recommended Textbooks

51F30 Lipschitz and coarse geometry

Overview

Lipschitz and coarse geometry study metric spaces up to controlled distortion, emphasizing large-scale structure.

Related Wikipedia Page

Wikipedia: Coarse geometry

Useful Links

Key Ideas

  • quasi-isometries
  • coarse invariants
  • metric distortion

Typical Uses

This viewpoint is important in geometric group theory and the analysis of spaces at large scales.

Applications

  • Geometric group theory
  • Network analysis
  • Metric spaces

References

Recommended Textbooks