- This page concerns mathematician Sergei Novikov's topology conjecture. For astrophysicist Igor Novikov's conjecture regarding time travel, see Novikov self-consistency principle.
The Novikov conjecture concerns the homotopy invariance of certain polynomials in the Pontryagin classes of a manifold, arising from the fundamental group. According to the Novikov conjecture, the higher signatures, which are certain numerical invariants of smooth manifolds, are homotopy invariants.
The conjecture has been proved for finitely generated abelian groups. It is not yet known whether the Novikov conjecture holds true for all groups. There are no known counterexamples to the conjecture.
Precise formulation of the conjecture
be a continuous map from a closed oriented n-dimensional manifold M to BG, and
Novikov considered the numerical expression, found by evaluating the cohomology class in top dimension against the fundamental class [M], and known as a higher signature:
where Li is the ith Hirzebruch polynomial, or sometimes (less descriptively) as the ith L-polynomial. For each i, this polynomial can be expressed in the Pontryagin classes of the manifold's tangent bundle. The Novikov conjecture states that the higher signature is an invariant of the oriented homotopy type of M for every such map f and every such class x, in other words, if is an orientation preserving homotopy equivalence, the higher signature associated to is equal to that associated to f.
Connection with the Borel conjecture
The Novikov conjecture is equivalent to the rational injectivity of the assembly map in L-theory. The Borel conjecture on the rigidity of aspherical manifolds is equivalent to the assembly map being an isomorphism.
- Davis, James F. (2000), "Manifold aspects of the Novikov conjecture", in Cappell, Sylvain; Ranicki, Andrew; Rosenberg, Jonathan, Surveys on surgery theory. Vol. 1 (PDF), Annals of Mathematics Studies, Princeton University Press, pp. 195–224, ISBN 978-0-691-04937-3, MR 1747536
- S. P. Novikov, Algebraic construction and properties of Hermitian analogs of k-theory over rings with involution from the point of view of Hamiltonian formalism. Some applications to differential topology and to the theory of characteristic classes. Izv.Akad.Nauk SSSR, v. 34, 1970 I N2, pp. 253-288; II: N3, pp. 475-500. English summary in Actes Congr. Intern. Math., v. 2, 1970, pp. 39-45.
- Biography of Sergei Novikov
- Novikov Conjecture Bibliography
- Novikov Conjecture 1993 Oberwolfach Conference Proceedings, Volume 1
- Novikov Conjecture 1993 Oberwolfach Conference Proceedings, Volume 2
- 2004 Oberwolfach Seminar notes on the Novikov Conjecture (pdf)
- Scholarpedia article by S.P. Novikov (2010)
- The Novikov Conjecture at the Manifold Atlas