nLab equivariant algebraic K-theory

Idea

The equivariant cohomology/equivariant spectrum-version of algebraic K-theory.

Properties

Rector completion theorem

(equivariant) cohomology	representing spectrum	equivariant cohomology of the point $\ast$	cohomology of classifying space $B G$
(equivariant) ordinary cohomology	HZ	Borel equivariance $H^\bullet_G(\ast) \simeq H^\bullet(B G, \mathbb{Z})$
(equivariant) complex K-theory	KU	representation ring $KU_G(\ast) \simeq R_{\mathbb{C}}(G)$	Atiyah-Segal completion theorem $R(G) \simeq KU_G(\ast) \overset{ \text{compl.} }{\longrightarrow} \widehat {KU_G(\ast)} \simeq KU(B G)$
(equivariant) complex cobordism cohomology	MU	$MU_G(\ast)$	completion theorem for complex cobordism cohomology $MU_G(\ast) \overset{ \text{compl.} }{\longrightarrow} \widehat {MU_G(\ast)} \simeq MU(B G)$
(equivariant) algebraic K-theory	$K \mathbb{F}_p$	representation ring $(K \mathbb{F}_p)_G(\ast) \simeq R_p(G)$	Rector completion theorem $R_{\mathbb{F}_p}(G) \simeq K (\mathbb{F}_p)_G(\ast) \overset{ \text{compl.} }{\longrightarrow} \widehat {(K \mathbb{F}_p)_G(\ast)} \!\! \overset{\text{<a href="https://ncatlab.org/nlab/show/Rector+completion+theorem">Rector 73</a>}}{\simeq} \!\!\!\!\!\! K \mathbb{F}_p(B G)$
(equivariant) stable cohomotopy	$K \mathbb{F}_1 \overset{\text{<a href="stable cohomotopy#StableCohomotopyIsAlgebraicKTheoryOverFieldWithOneElement">Segal 74</a>}}{\simeq}$ S	Burnside ring $\mathbb{S}_G(\ast) \simeq A(G)$	Segal-Carlsson completion theorem $A(G) \overset{\text{<a href="https://ncatlab.org/nlab/show/Burnside+ring+is+equivariant+stable+cohomotopy+of+the+point">Segal 71</a>}}{\simeq} \mathbb{S}_G(\ast) \overset{ \text{compl.} }{\longrightarrow} \widehat {\mathbb{S}_G(\ast)} \!\! \overset{\text{<a href="https://ncatlab.org/nlab/show/Segal-Carlsson+completion+theorem">Carlsson 84</a>}}{\simeq} \!\!\!\!\!\! \mathbb{S}(B G)$

Related concepts

• equivariant Adams conjecture

• equivariant K-theory

• equivariant elliptic cohomology

References

• Wolfgang Lück, Transformation Groups and Algebraic K-Theory, Lecture Notes in Mathematics 1408 (Springer 1989) (doi:10.1007/BFb0083681)

• Z. Fiedorowicz, H. Hauschild, Peter May, theorem 0.4 of Equivariant algebraic K-theory, Equivariant algebraic K-theory, Algebraic K-Theory. Springer, Berlin, Heidelberg, 1982. 23-80 (pdf)

• Henning Hauschild, Stefan Waner, theorem 0.1 of The equivariant Dold theorem mod $k$ and the Adams conjecture, Illinois J. Math. Volume 27, Issue 1 (1983), 52-66. (euclid:1256065410)

• Kazuhisa Shimakawa, Note on the equivariant $K$-theory spectrum, Publ. RIMS, Kyoto Univ. 29 (1993), 449-453 (pdf, doi:10.2977/prims/1195167052)

• Christopher French, theorem 2.4 in The equivariant $J$–homomorphism for finite groups at certain primes, Algebr. Geom. Topol. Volume 9, Number 4 (2009), 1885-1949 (euclid:1513797069)