Title The Steenrod problem of realizing polynomial cohomology rings
Authors Kasper Andersen, Jesper Grodal
Alternative Location http://jtopol.oxfordjournal..., Restricted Access
Alternative Location http://dx.doi.org/10.1112/j..., Restricted Access
Publication Journal of Topology
Year 2008
Volume 1
Issue 4
Pages 747 - 760
Document type Article
Status Published
Quality controlled Yes
Language eng
Publisher Oxford UP / London Mathematical Society
Abstract English In this paper, we completely classify which graded polynomial<br> R-algebras in finitely many even degree variables can occur as the singular cohomology of a space with coefficients in R, a 1960 question of N. E. Steenrod, for a commutative ring R satisfying mild conditions. In the fundamental case R=Z, our result states that the only polynomial cohomology rings over Z that can occur are tensor products of copies of $H^*(CP^\infty;Z)\cong Zx_2$,<br> $H^*(BSU(n);Z)\cong Zx_4, x_6, \ldots, x_{2n}$, and<br> $H^*(BSp(n);Z)\cong Zx_4, x_8, \ldots, x_{4n}$, confirming an old conjecture. Our classification extends Notbohm&#39;s solution for $R=F_p$, p odd. Odd degree generators, excluded above, only occur if R is an $F_2$-algebra and in that case the recent classification of<br> 2-compact groups by the authors can be used instead of the present paper. Our proofs are short and rely on the general theory of<br> p-compact groups, but not on classification results for these.
ISBN/ISSN/Other ISSN: 1753-8424 (online)

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