nLab cobordism theory determining homology theory

Contents

Context

Algebraic topology

Higher algebra

Contents

Idea

Given a multiplicative cohomology theory, hence an E-∞ ring EE, equipped with a multiplicative universal orientation for manifolds with G-structure, hence a homomorphism of E ∞E_\infty-rings MG⟶EM G \longrightarrow E from the GG-Thom spectrum MGM G, then EE canonically becomes an MGM G-∞-module and so one may consider the functor

X↦MG •(X)⊗ MG •E •. X \mapsto M G_\bullet(X) \otimes_{M G_\bullet} E_\bullet \,.

If this is, first of all, a generalized homology theory itself, hence represented by a spectrum, then one may ask if this spectrum coincides with the original EE, hence if there is an natural equivalence

MG •(−)⊗ MG •E •≃E •(−). M G_\bullet(-) \otimes_{M G_\bullet} E_\bullet \simeq E_\bullet(-) \,.

If so, one often says that the cobordism theory determines the homology theory (e.g. Hopkins & Hovey 1992).

Examples

Originally this was shown to be the case by Conner & Floyd 1966, see Conner-Floyd isomorphism) for E=E= KU with its canonical complex orientation MU→KUMU \to KU (they also showed the case for KO with MSp →\toKO). Later the Landweber exact functor theorem (Landweber 76) generalized this to all complex oriented cohomology theories MU→E\to E.

The generalization to the actual Atiyah-Bott-Shapiro orientations of topological K-theory, namely MSpinc →\to KU and MSpin →\to KO is due to (Hopkins-Hovey 92).

For elliptic cohomology with the SO orientation of elliptic cohomology MSO→EllM SO \to Ell the statement is due to (Landweber-Ravenel-Stong 93). For the refinement to the spin orientation of elliptic cohomology of (Kreck-Stolz 93) a statement is due to (Hovey 95).

Refereces

Last revised on October 7, 2025 at 18:38:13. See the history of this page for a list of all contributions to it.