Is there a known relation between the space of units of a ring spectrum, from stable homotopy theory in the sense of Ando-Blumberg-Gepner https://arxiv.org/pdf/1002.3004v2.pdf and completions of spectra, in the sense of Bousfield -Kan, et al?

In particular, does completion commute with p- completion at a prime p? Since the first is a homotopy colimit like tipe of construction, and the second one is a homotopy inverse limit, this seems to be unlikely. Is there a spectral sequence relating them ?

  • 2
    $\begingroup$ I don't understand the relationship between the second paragraph and the first. $\endgroup$ – Qiaochu Yuan Nov 18 '16 at 1:30
  • 2
    $\begingroup$ Are you asking if taking units commutes with p-completion? If so, then the answer is no because it is also false for ordinary rings: $(R^\wedge_p)^\times \neq (R^\times)^\wedge_p$ as you can see from the example of $\Bbb Z$. However, the issue is almost entirely a $\pi_0$-issue. $\endgroup$ – Tyler Lawson Nov 18 '16 at 5:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.