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Aug 22, 2015 at 13:57 comment added user51223 If this still counts important, by work of Wahl an analogous result of Madsen-Wiess holds in unoriented case: Let $MTO(2)=:BO(2)^{-\gamma_2}$ with $\gamma_2\to BO(2)$ being the canonicla bundle. Then the moduli $\mathcal{N}_\infty$ for unoriented surfaces is homotopy equivalent to $\Omega^\infty MTO(2)$. Now, $\mathbb{R} P_{-1}$ is related to this by a cofibration of spectra $$MTO(2)\to BO(2)_+\to\mathbb{R} P_{-1}$$ which lead to a fibration of infinite loop spaces $$\Omega^\infty MTO(2)\to QBO(2)_+\to \Omega^\infty\mathbb{R}P_{-1}.$$ Found this when searching for `root invariant'.
Jan 29, 2014 at 10:29 history edited Neil Strickland CC BY-SA 3.0
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Jan 29, 2014 at 10:14 history answered Neil Strickland CC BY-SA 3.0