the Hopf invariant is a homotopy invariant of certain maps between n-spheres. In 1931 Heinz Hopf used Clifford parallels to construct the Hopf map η...
8 KB (1,542 words) - 06:38, 26 September 2024
this time Hopf discovered the Hopf invariant of maps S 3 → S 2 {\displaystyle S^{3}\to S^{2}} and proved that the Hopf fibration has invariant 1. In the...
11 KB (970 words) - 05:12, 25 July 2024
In differential topology, the Hopf fibration (also known as the Hopf bundle or Hopf map) describes a 3-sphere (a hypersphere in four-dimensional space)...
36 KB (4,813 words) - 13:13, 9 April 2025
M^{4m+2}} (for m ≠ 0 , 1 , 3 {\displaystyle m\neq 0,1,3} ) and the mod 2 Hopf invariant of maps S 4 m + 2 + k → S 2 m + 1 + k {\displaystyle S^{4m+2+k}\to S^{2m+1+k}}...
17 KB (2,366 words) - 19:50, 30 May 2025
The Hopf theorem (named after Heinz Hopf) is a statement in differential topology, saying that the topological degree is the only homotopy invariant of...
967 bytes (103 words) - 17:44, 10 October 2020
H-space (redirect from Hopf space)
It is clear how to define a homotopy from [f][g] to [g][f]. Adams' Hopf invariant one theorem, named after Frank Adams, states that S0, S1, S3, S7 are...
6 KB (756 words) - 15:17, 18 March 2025
1958 J. Frank Adams published a further generalization in terms of Hopf invariants on H-spaces which still limits the dimension to 1, 2, 4, or 8. It was...
27 KB (3,215 words) - 22:17, 5 June 2025
Linking number (category Knot invariants)
differential point of view Hopf invariant – Homotopy invariant of maps between n-spheres Kissing number – Geometric concept Writhe – Invariant of a knot diagram...
16 KB (2,527 words) - 08:36, 5 March 2025
Homotopy groups of spheres (section Hopf fibrations)
S^{15}\hookrightarrow S^{31}\rightarrow S^{16},} the first non-trivial case of the Hopf invariant one problem, because such a fibration would imply that the failed relation...
83 KB (8,124 words) - 04:10, 28 March 2025
classical case. He used this spectral sequence to attack the celebrated Hopf invariant one problem, which he completely solved in a 1960 paper by making a...
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In complex geometry, a Hopf surface is a compact complex surface obtained as a quotient of the complex vector space (with zero deleted) C 2 ∖ { 0 } {\displaystyle...
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In mathematical knot theory, the Hopf link is the simplest nontrivial link with more than one component. It consists of two circles linked together exactly...
9 KB (892 words) - 16:20, 15 November 2022
In mathematics, the Hopf decomposition, named after Eberhard Hopf, gives a canonical decomposition of a measure space (X, μ) with respect to an invertible...
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Princeton in 1955. His other collaborators included; J. Frank Adams (Hopf invariant problem), Jürgen Berndt (projective planes), Roger Bielawski (Berry–Robbins...
83 KB (8,832 words) - 18:56, 18 May 2025
Knot theory (redirect from Hyperbolic invariant)
distinguished using a knot invariant, a "quantity" which is the same when computed from different descriptions of a knot. Important invariants include knot polynomials...
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to coproducts, counits and antipodes of Hopf algebras. Since the Vassiliev invariants (or finite type invariants) are closely related to chord diagrams...
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Reshetikhin–Turaev invariants (RT-invariants) are a family of quantum invariants of framed links. Such invariants of framed links also give rise to invariants of 3-manifolds...
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Link group (redirect from Milnor's invariants)
Milnor invariants of length k + 1 are defined if all Milnor invariants of length less than or equal to k vanish. The first (2-fold) Milnor invariant is simply...
8 KB (1,236 words) - 19:46, 18 December 2023
nontrivial example of a link with more than one component is called the Hopf link, which consists of two circles (or unknots) linked together once. The...
8 KB (1,107 words) - 22:47, 20 February 2025
H_{n}(X;\mathbb {Z} ).} Fibration Hopf fibration Hopf invariant Knot theory Homotopy class Homotopy groups of spheres Topological invariant Homotopy group with coefficients...
20 KB (3,432 words) - 14:48, 25 May 2025
One way to answer the question is using knot polynomials, which are invariants of the knot. If two diagrams have different polynomials, they represent...
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to the Yang–Baxter equation (see § Basic properties); and in monodromy invariants of algebraic geometry. In this introduction let n = 4; the generalization...
36 KB (4,891 words) - 07:38, 7 June 2025
In mathematics, and especially gauge theory, Seiberg–Witten invariants are invariants of compact smooth oriented 4-manifolds introduced by Edward Witten (1994)...
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spheres" by R. Bott and J. Milnor and "On the nonexistence of elements of Hopf invariant one" by J. F. Adams". Bulletin of the American Mathematical Society...
25 KB (3,088 words) - 15:48, 11 November 2024
Steenrod algebra (category Hopf algebras)
appropriate Adem relations, was the solution by J. Frank Adams of the Hopf invariant one problem. One application of the mod 2 Steenrod algebra that is fairly...
30 KB (5,577 words) - 03:49, 29 May 2025
structure of a Hopf algebra is when considering all H-modules as a category. The additional structure is also used to define invariant elements of an...
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In the mathematical field of knot theory, a knot invariant is a quantity (in a broad sense) defined for each knot which is the same for equivalent knots...
10 KB (1,278 words) - 16:18, 12 January 2025
They were introduced by J. Frank Adams (1960) in his solution to the Hopf invariant problem. Similarly, one can define tertiary cohomology operations from...
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Topological K-theory has been applied in John Frank Adams’ proof of the “Hopf invariant one” problem via Adams operations. Adams also proved an upper bound...
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Alexander polynomial (redirect from Alexander invariant)
In mathematics, the Alexander polynomial is a knot invariant which assigns a polynomial with integer coefficients to each knot type. James Waddell Alexander...
17 KB (2,622 words) - 22:00, 9 May 2025