In this paper, we use the KK–theory of Kasparov to prove exactness of sequences relating the K–theory of a real C∗–algebra and of its complexification (generalizing results of Boersema). We use this to relate the real version of the Baum-Connes conjecture for a discrete group to its complex counterpart. In particular, the complex Baum–Connes assembly map is an isomorphism if and only if the real one is, thus reproving a result of Baum and Karoubi. After inverting 2, the same is true for the injectivity or surjectivity part alone.
Schick, Thomas  1
@article{10_2140_agt_2004_4_333,
author = {Schick, Thomas},
title = {Real versus complex {K{\textendash}theory} using {Kasparov{\textquoteright}s} bivariant {KK{\textendash}theory}},
journal = {Algebraic and Geometric Topology},
pages = {333--346},
year = {2004},
volume = {4},
number = {1},
doi = {10.2140/agt.2004.4.333},
url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2004.4.333/}
}
TY - JOUR AU - Schick, Thomas TI - Real versus complex K–theory using Kasparov’s bivariant KK–theory JO - Algebraic and Geometric Topology PY - 2004 SP - 333 EP - 346 VL - 4 IS - 1 UR - http://geodesic.mathdoc.fr/articles/10.2140/agt.2004.4.333/ DO - 10.2140/agt.2004.4.333 ID - 10_2140_agt_2004_4_333 ER -
Schick, Thomas. Real versus complex K–theory using Kasparov’s bivariant KK–theory. Algebraic and Geometric Topology, Tome 4 (2004) no. 1, pp. 333-346. doi: 10.2140/agt.2004.4.333
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