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Jeffrey L. Boersema and Terry A. Loring
K-theory for real C*-algebras via unitary elements with symmetries view print
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| Published: |
September 30, 2016 |
| Keywords: |
topological insulator, semiprojectivity, K-theory, E-theory, ten-fold way |
| Subject: |
46L80, 19K99, 81Q99 |
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Abstract
We prove that all eight KO groups for a real C*-algebra can be
constructed from homotopy classes of unitary matrices that respect
a variety of symmetries. In this manifestation of the KO groups,
all eight boudary maps in the 24-term exact sequences associated to an
ideal in a real C*-algebra can be computed as exponential or
index maps with formulas that are nearly identical to the complex case.
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| Acknowledgements
This work was partially supported by a grant from the Simons Foundation (208723 to Loring).
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| Author information
Jeffrey L. Boersema:
Seattle University, Department of Mathematics, Seattle, Washington 98133, USA
boersema@seattleu.edu
Terry A. Loring:
University of New Mexico, Department of Mathematics and Statistics, Albuquerque, New Mexico 87131, USA
loring@math.unm.edu
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