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 ⓘ