New York Journal of Mathematics
NYJM Monographs, Volume 7, 2025

  

Donald M. Davis

The connective KO theory of the Eilenberg-MacLane space K(Z/2,2)

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Published: March 2, 2026
Keywords: Adams spectral sequence, connective KO-theory, Eilenberg-MacLane space, Stiefel-Whitney classes.
Subject[2010]: 55T15, 55N20, 55N15, 57R20.

Abstract

We compute ko*(K(Z/2,2)) and ko*(K(Z/2,2)), the connective KO-homology and -cohomology groups of the mod 2 Eilenberg-MacLane space K(Z/2,2), using the Adams spectral sequence. The work relies heavily on work done several years earlier for the (complex) ku groups by the author and W. S. Wilson. We illustrate an interesting duality relation between the ko-homology and -cohomology groups. We deduce a new result about Stiefel-Whitney classes in Spin manifolds.


Acknowledgements

We thank the referee for comments which led to improvement of exposition.


Author information

Donald M. Davis:
Department of Mathematics
Lehigh University
Bethlehem, PA 18015, USA

dmd1@lehigh.edu