Whitehead product in homotopy theory
E886920
The Whitehead product in homotopy theory is a bilinear operation on homotopy groups that captures how spheres can be nontrivially linked or composed within a topological space.
Observed surface forms (1)
| Surface form | Occurrences |
|---|---|
| Whitehead product | 0 |
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
algebraic operation
ⓘ
bilinear operation on homotopy groups ⓘ construction in homotopy theory ⓘ |
| actsOn |
homotopy groups
ⓘ
π_m(X) ⓘ π_n(X) ⓘ |
| appearsIn |
homotopy spectral sequences
ⓘ
long exact sequences of homotopy groups for pairs ⓘ |
| arity | binary operation ⓘ |
| captures |
interaction of homotopy classes of maps from spheres
ⓘ
linking behavior of spheres in a space ⓘ nontrivial compositions of sphere maps ⓘ |
| codomain | π_{n+m-1}(X) ⓘ |
| constructionUses |
attaching map from S^{m+n-1} to S^m ∨ S^n
ⓘ
commutator-like map on spheres ⓘ wedge sum S^m ∨ S^n ⓘ |
| context | graded homotopy groups π_*(X) ⓘ |
| definedIn | homotopy category of pointed spaces ⓘ |
| domainCondition | α ∈ π_m(X), β ∈ π_n(X) ⓘ |
| field | algebraic topology ⓘ |
| firstIntroducedBy | J. H. C. Whitehead NERFINISHED ⓘ |
| generalizes | commutator in fundamental groups ⓘ |
| gives | higher order operations in homotopy ⓘ |
| isDefinedFor | pointed topological spaces ⓘ |
| isToolFor |
detecting nontrivial elements in homotopy groups
ⓘ
studying attaching maps of cells in CW-complexes ⓘ |
| isZeroFor | simply connected suspensions under suitable conditions ⓘ |
| namedAfter | J. H. C. Whitehead NERFINISHED ⓘ |
| nontrivialExample |
Hopf invariant phenomena in homotopy groups of spheres
ⓘ
[ι_n,ι_n] in π_{2n-1}(S^n) for n>1 ⓘ |
| outputCondition | [α,β] ∈ π_{m+n-1}(X) ⓘ |
| property |
bilinear
ⓘ
functorial ⓘ graded skew-commutative ⓘ natural with respect to continuous maps ⓘ |
| relatedTo |
Lie algebra structure on homotopy groups of an H-space
ⓘ
Samelson product NERFINISHED ⓘ |
| requires | chosen basepoint ⓘ |
| satisfies |
[α,β] = −(−1)^{mn}[β,α] for α∈π_m, β∈π_n
ⓘ
graded Jacobi identity up to sign ⓘ |
| structureType | graded Lie algebra up to homotopy ⓘ |
| usedIn |
Postnikov tower computations
ⓘ
description of k-invariants ⓘ homotopy Lie algebra of a space ⓘ obstruction theory ⓘ study of homotopy groups of spheres ⓘ |
| vanishesOn | H-spaces under suitable conditions ⓘ |
| yearIntroducedApprox | mid 20th century ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.