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9 votes
0 answers
317 views

Are there non-obvious finite $E_\infty$ ring spectra?

I see two "obvious" classes of nonzero finite $E_\infty$ ring spectra $R$: $R = \Sigma^\infty_+ (S^1)^{\times n}$ $R = D\Sigma^\infty_+ X$ ($X$ a finite space) Questions: Are there any others? In ...
Tim Campion's user avatar
8 votes
0 answers
300 views

What can I say about an $E_\infty$ ring spectrum with an odd invertible element?

I have an $E_\infty$ ring spectrum $R$. I suspect it is trivial, but I'm not sure. What I do know is that there is an $R$-linear equivalence $R \simeq \Sigma R$. Unless I am very confused, this ...
Theo Johnson-Freyd's user avatar
8 votes
0 answers
328 views

Did the Goerss-Hopkins manuscript "Multiplicative stable homotopy theory" ever appear?

A citation to "M. J. Hopkins and P. Goerss, Multiplicative stable homotopy theory, unpublished manuscript, 1996" appears in the Hill, Hopkins, Ravenel Annals paper on the Kervaire invariant. It was ...
David White's user avatar
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5 votes
0 answers
173 views

Uniqueness of complex topological $K$-theory as an $S$-algebra

This might be well-known or trivial, but I could not figure out how to fill in the details: For an $S$-algebra $K$ denote its associated multiplicative cohomology theory by $h^*_K$. Suppose that I ...
Ulrich Pennig's user avatar
3 votes
0 answers
434 views

Units of a ring spectrum

Is there a good notion of the spectrum of units $R^\ast$ in a (possibly non-connective) $E_\infty$-ring spectrum $R$? A standard definition (see section 1.2 in http://arxiv.org/abs/0810.4535) seems ...
unit's user avatar
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