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18Dxx Categorical structures

This subtopic studies categorical structures, including internal objects, fibrations, and enriched constructions that organize mathematics at a structural level.

Specific topics

18D05 Double categories, $2$-categories, bicategories

Overview

18D05 studies functor categories and diagram categories in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Functor categories and diagram categories (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for functor categories and diagram categories
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D10 Monoidal, symmetric monoidal and braided categories

Overview

18D10 studies natural transformations and coherence in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Natural transformations and coherence (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for natural transformations and coherence
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D15 Closed categories (closed monoidal and Cartesian closed categories, etc.)

Overview

18D15 studies adjunctions and monads in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Adjunctions and monads (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for adjunctions and monads
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D20 Enriched categories

Overview

18D20 studies limits, colimits, and completeness in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Limits, colimits, and completeness (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for limits, colimits, and completeness
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D25 Strong functors, strong adjunctions

Overview

18D25 studies factorization systems and exactness in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Factorization systems and exactness (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for factorization systems and exactness
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D30 Fibered categories

Overview

18D30 studies enriched and internal categorical structures in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Enriched and internal categorical structures (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for enriched and internal categorical structures
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D35 Structured objects in a $2$-category

Overview

18D35 studies closed categories and tensor structures in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Closed categories and tensor structures (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for closed categories and tensor structures
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D40 Internal categories, diagrams

Overview

18D40 studies monoidal and symmetric monoidal categories in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Monoidal and symmetric monoidal categories (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for monoidal and symmetric monoidal categories
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D50 Operads, multicategories, modular operads

Overview

18D50 studies higher-dimensional categorical structures in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Higher-dimensional categorical structures (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for higher-dimensional categorical structures
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D60 $n$-categories for $n \geq 3$

Overview

18D60 studies 2-categories and bicategories in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

2-categories and bicategories (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for 2-categories and bicategories
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks

18D70 Cartesian closed categories, topos-theoretic methods

Overview

18D70 studies miscellaneous categorical structures in categorical structures. It studies the internal structural features of categories themselves, including limits, adjunctions, enrichment, and higher-dimensional coherence.

Related Wikipedia Page

Miscellaneous categorical structures (Wikipedia)

Useful Links

Key Ideas

  • Canonical formulations and representative examples for miscellaneous categorical structures
  • How structural, local, and computational viewpoints interact in the subject
  • Standard theorem patterns and invariants used in current research practice

Typical Uses

Used to formalize and compare categorical constructions across algebra, topology, and logic.

Applications

  • Limits and adjunctions
  • Enrichment and monoidal structure
  • Higher-dimensional category theory

References

Recommended Textbooks