Hopf invariant

E679320

The Hopf invariant is a topological integer-valued invariant that classifies certain continuous maps between spheres, playing a central role in homotopy theory and the study of higher-dimensional linking.

All labels observed (4)

Label Occurrences
Hopf invariant canonical 5
Hopf degree theorem 2
Hopf invariant one problem 1

How this entity was disambiguated

Statements (48)

Predicate Object
instanceOf homotopy invariant
integer-valued invariant
topological invariant
appearsIn Adams’s solution of the Hopf invariant one problem
obstruction theory
rational homotopy theory
study of H-spaces
appliesTo continuous maps between spheres
maps S^{2n-1} → S^n
centralIn Hopf invariant one problem
linked to: Hopf invariant
constraint Hopf invariant one maps exist only in dimensions 1, 2, 4, and 8
context CW-complex mapping cones
maps between spheres of odd dimension domain
definedOn homotopy classes of maps
definedUsing cellular decomposition of mapping cone
cohomology operations
cup product in cohomology
field algebraic topology
homotopy theory
generalization Massey products
secondary cohomology operations
hasSpecialCase Hopf invariant of the Hopf fibration S^7 → S^4 equals 1
Hopf invariant of the Hopf fibration S^{15} → S^8 equals 1
Hopf invariant of the Hopf map S^3 → S^2 equals 1
hasVariant mod p Hopf invariant
linked to: Hopf invariant

reduced Hopf invariant
stable Hopf invariant
implies existence of higher-dimensional linking phenomena
namedAfter Heinz Hopf
property additive under composition in certain contexts
homotopy invariant of maps
relatedTo Adams spectral sequence
Hopf fibration
J-homomorphism
Whitehead product
cohomology cup product
complex numbers
linking number
normed division algebras
octonions
quaternions
real numbers
stable homotopy groups of spheres
usedFor classification of certain homotopy classes of maps between spheres
distinguishing non-homotopic maps with same degree
study of higher-dimensional linking
usedToProve nontriviality of certain homotopy groups of spheres
valueType integer

How these facts were elicited

Referenced by (9)

Full triples — surface form annotated when it differs from this entity's canonical label.

Heinz Hopf notableWork Hopf invariant
Heinz Hopf notableWork Hopf degree theorem
linked to: Hopf invariant
Heinz Hopf notableFor Hopf invariant
subject linked to: Hopf
Heinz Hopf notableFor Hopf degree theorem
subject linked to: Hopf
linked to: Hopf invariant
Heinz Hopf notableFor Hopf invariant
subject linked to: Gräbschen
Hopf invariant centralIn Hopf invariant one problem
linked to: Hopf invariant
Hopf invariant hasVariant mod p Hopf invariant
linked to: Hopf invariant
Über die Abbildungen der dreidimensionalen Sphäre auf die Kugelfläche relatedConcept Hopf invariant