Brown representability theorem
E886929
The Brown representability theorem is a fundamental result in homotopy theory and category theory that characterizes when a contravariant functor from a homotopy category to sets (or abelian groups) is representable, providing a powerful tool for constructing and understanding cohomology theories.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
mathematical theorem
ⓘ
result in category theory ⓘ result in homotopy theory ⓘ |
| appliesTo |
contravariant functors from homotopy categories to abelian groups
ⓘ
contravariant functors from homotopy categories to sets ⓘ |
| characterizes | when a contravariant functor is representable ⓘ |
| concerns |
cohomology theories
ⓘ
contravariant functors ⓘ homotopy category ⓘ representable functors ⓘ |
| context |
homotopy category of CW complexes
ⓘ
triangulated categories ⓘ |
| ensures |
cohomology functors are representable
ⓘ
existence of representing objects for suitable functors ⓘ |
| field |
algebraic topology
ⓘ
category theory ⓘ homotopy theory ⓘ |
| generalizationOf | classical representability results in category theory ⓘ |
| givesConditionOn |
abelian-group-valued functors on homotopy categories
ⓘ
set-valued functors on homotopy categories ⓘ |
| hasVariant |
Brown representability for homology
ⓘ
Brown representability in triangulated categories ⓘ |
| historicalPeriod | 20th century mathematics ⓘ |
| implies |
Eilenberg–Steenrod type representability results
ⓘ
existence of representing spaces for cohomology theories ⓘ |
| mathematicalArea |
homological algebra
ⓘ
stable homotopy theory ⓘ |
| namedAfter | Edgar H. Brown Jr. NERFINISHED ⓘ |
| relatedTo |
Eilenberg–Steenrod axioms
NERFINISHED
ⓘ
Freyd adjoint functor theorem NERFINISHED ⓘ Yoneda lemma NERFINISHED ⓘ |
| requires |
exactness with respect to homotopy cofiber sequences
ⓘ
wedge axiom for functors ⓘ |
| status |
fundamental result in algebraic topology
ⓘ
standard tool in modern homotopy theory ⓘ |
| toolFor |
constructing cohomology theories
ⓘ
understanding generalized cohomology theories ⓘ |
| type | representability theorem ⓘ |
| typicalCodomain |
category of abelian groups
ⓘ
category of sets ⓘ |
| typicalDomain | homotopy category of pointed CW complexes ⓘ |
| usedIn |
derived categories
ⓘ
spectra and generalized cohomology ⓘ stable homotopy theory ⓘ triangulated category theory ⓘ |
| usedToShow |
generalized cohomology theories are represented by spectra
ⓘ
ordinary cohomology is represented by Eilenberg–Mac Lane spaces ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.