How are characteristic classes morphisms of infinite loop spaces? (if they are)Group Completions and Infinite-Loop SpacesCommutativity of a diagram of boundary morphisms from the long exact sequence of homotopy groups of a fibration and its loop spacesWhat are the algebras over $Omega^kSigma^k$ ?$mathcalI$-functors and infinite loop spacesInfinite loop of a p-completed specta vs p-completion of infinite loop of the spectraComonadicity of spaces over spectra?Is there a fibration sequence of spectra $KmathbbF_qto KUto KU$?Homology of spectra vs homology of infinite loop spacesEquivalent definitions of Thom spectra

How are characteristic classes morphisms of infinite loop spaces? (if they are)


Group Completions and Infinite-Loop SpacesCommutativity of a diagram of boundary morphisms from the long exact sequence of homotopy groups of a fibration and its loop spacesWhat are the algebras over $Omega^kSigma^k$ ?$mathcalI$-functors and infinite loop spacesInfinite loop of a p-completed specta vs p-completion of infinite loop of the spectraComonadicity of spaces over spectra?Is there a fibration sequence of spectra $KmathbbF_qto KUto KU$?Homology of spectra vs homology of infinite loop spacesEquivalent definitions of Thom spectra













10















$begingroup$


The direct sum of real vector bundles endows $BO=mathrmcolim BO(n)$ with a natural structure of abelian group up to homotopy. The same applies to the classifying spaces of all groups in the Whitehead tower of $O$, i.e., one has a natural structure of abelian group up to homotopy on $BSO$, $BSpin$, $BString$, etc.



As $w(Eoplus F)=w(E)cup w(F)$ one sees that
$$
w_1colon BO to K(mathbbZ/2mathbbZ,1)
$$

is a morphism of abelian groups up to homotopy, and that similarly
$$
w_2colon BSO to K(mathbbZ/2mathbbZ,2)
$$

is a morphism of abelian groups up to homotopy. One can even make a step further and see
$$
BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)
$$

and
$$
BSpin to BSOxrightarroww_2 K(mathbbZ/2mathbbZ,2)
$$

as ``short exact sequences of abelian groups up to homotopy''.



One can be more ambitious here. Not only $BO$ is an abelian group up to homotopy, but it is an $infty$-loop space, i.e. $BO=Omega^infty bo$ for a certain connective spectrum $bo$. The same applies to $BSO$, $BSpin$,etc., and it also applies to $K(mathbbZ/2mathbbZ,n)$ as $K(mathbbZ/2mathbbZ,n)=Omega^inftySigma^n HmathbbZ/2$. So one may hope that the above sequences are actually infinitely deloopable and come from fibrations
$$
bso to boxrightarrowOmega^-inftyw_1 Sigma HmathbbZ/2
$$

and
$$
bspin to bsoxrightarrowOmega^-inftyw_2 Sigma^2 HmathbbZ/2
$$

of connective spectra. Versions of this latter statement seem to appear in the literature, at least in the form "$BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)$ is a fibration of infinite loop spaces" which however I am only able to give a precise meaning by interpreting it as above. For instance one finds: "Recall that $BSpin^c$ participates in a fibration of infinite loop spaces $K(mathbbZ,2)to BSpin^cto BSOxrightarrowbw_2K(mathbbZ,3)$'' in section 7 of Ando-Blumberg-Gepner's Twists of K-theory and TMF.



My question is:



  • Is it true that the above are indeed fibrations of connective spectra inducing the usual fibrations of topological spaces via $Omega^infty$?


  • Where can I find a rigorous proof of this statement?










share|cite|improve this question









$endgroup$



















    10















    $begingroup$


    The direct sum of real vector bundles endows $BO=mathrmcolim BO(n)$ with a natural structure of abelian group up to homotopy. The same applies to the classifying spaces of all groups in the Whitehead tower of $O$, i.e., one has a natural structure of abelian group up to homotopy on $BSO$, $BSpin$, $BString$, etc.



    As $w(Eoplus F)=w(E)cup w(F)$ one sees that
    $$
    w_1colon BO to K(mathbbZ/2mathbbZ,1)
    $$

    is a morphism of abelian groups up to homotopy, and that similarly
    $$
    w_2colon BSO to K(mathbbZ/2mathbbZ,2)
    $$

    is a morphism of abelian groups up to homotopy. One can even make a step further and see
    $$
    BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)
    $$

    and
    $$
    BSpin to BSOxrightarroww_2 K(mathbbZ/2mathbbZ,2)
    $$

    as ``short exact sequences of abelian groups up to homotopy''.



    One can be more ambitious here. Not only $BO$ is an abelian group up to homotopy, but it is an $infty$-loop space, i.e. $BO=Omega^infty bo$ for a certain connective spectrum $bo$. The same applies to $BSO$, $BSpin$,etc., and it also applies to $K(mathbbZ/2mathbbZ,n)$ as $K(mathbbZ/2mathbbZ,n)=Omega^inftySigma^n HmathbbZ/2$. So one may hope that the above sequences are actually infinitely deloopable and come from fibrations
    $$
    bso to boxrightarrowOmega^-inftyw_1 Sigma HmathbbZ/2
    $$

    and
    $$
    bspin to bsoxrightarrowOmega^-inftyw_2 Sigma^2 HmathbbZ/2
    $$

    of connective spectra. Versions of this latter statement seem to appear in the literature, at least in the form "$BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)$ is a fibration of infinite loop spaces" which however I am only able to give a precise meaning by interpreting it as above. For instance one finds: "Recall that $BSpin^c$ participates in a fibration of infinite loop spaces $K(mathbbZ,2)to BSpin^cto BSOxrightarrowbw_2K(mathbbZ,3)$'' in section 7 of Ando-Blumberg-Gepner's Twists of K-theory and TMF.



    My question is:



    • Is it true that the above are indeed fibrations of connective spectra inducing the usual fibrations of topological spaces via $Omega^infty$?


    • Where can I find a rigorous proof of this statement?










    share|cite|improve this question









    $endgroup$

















      10













      10









      10


      3



      $begingroup$


      The direct sum of real vector bundles endows $BO=mathrmcolim BO(n)$ with a natural structure of abelian group up to homotopy. The same applies to the classifying spaces of all groups in the Whitehead tower of $O$, i.e., one has a natural structure of abelian group up to homotopy on $BSO$, $BSpin$, $BString$, etc.



      As $w(Eoplus F)=w(E)cup w(F)$ one sees that
      $$
      w_1colon BO to K(mathbbZ/2mathbbZ,1)
      $$

      is a morphism of abelian groups up to homotopy, and that similarly
      $$
      w_2colon BSO to K(mathbbZ/2mathbbZ,2)
      $$

      is a morphism of abelian groups up to homotopy. One can even make a step further and see
      $$
      BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)
      $$

      and
      $$
      BSpin to BSOxrightarroww_2 K(mathbbZ/2mathbbZ,2)
      $$

      as ``short exact sequences of abelian groups up to homotopy''.



      One can be more ambitious here. Not only $BO$ is an abelian group up to homotopy, but it is an $infty$-loop space, i.e. $BO=Omega^infty bo$ for a certain connective spectrum $bo$. The same applies to $BSO$, $BSpin$,etc., and it also applies to $K(mathbbZ/2mathbbZ,n)$ as $K(mathbbZ/2mathbbZ,n)=Omega^inftySigma^n HmathbbZ/2$. So one may hope that the above sequences are actually infinitely deloopable and come from fibrations
      $$
      bso to boxrightarrowOmega^-inftyw_1 Sigma HmathbbZ/2
      $$

      and
      $$
      bspin to bsoxrightarrowOmega^-inftyw_2 Sigma^2 HmathbbZ/2
      $$

      of connective spectra. Versions of this latter statement seem to appear in the literature, at least in the form "$BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)$ is a fibration of infinite loop spaces" which however I am only able to give a precise meaning by interpreting it as above. For instance one finds: "Recall that $BSpin^c$ participates in a fibration of infinite loop spaces $K(mathbbZ,2)to BSpin^cto BSOxrightarrowbw_2K(mathbbZ,3)$'' in section 7 of Ando-Blumberg-Gepner's Twists of K-theory and TMF.



      My question is:



      • Is it true that the above are indeed fibrations of connective spectra inducing the usual fibrations of topological spaces via $Omega^infty$?


      • Where can I find a rigorous proof of this statement?










      share|cite|improve this question









      $endgroup$




      The direct sum of real vector bundles endows $BO=mathrmcolim BO(n)$ with a natural structure of abelian group up to homotopy. The same applies to the classifying spaces of all groups in the Whitehead tower of $O$, i.e., one has a natural structure of abelian group up to homotopy on $BSO$, $BSpin$, $BString$, etc.



      As $w(Eoplus F)=w(E)cup w(F)$ one sees that
      $$
      w_1colon BO to K(mathbbZ/2mathbbZ,1)
      $$

      is a morphism of abelian groups up to homotopy, and that similarly
      $$
      w_2colon BSO to K(mathbbZ/2mathbbZ,2)
      $$

      is a morphism of abelian groups up to homotopy. One can even make a step further and see
      $$
      BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)
      $$

      and
      $$
      BSpin to BSOxrightarroww_2 K(mathbbZ/2mathbbZ,2)
      $$

      as ``short exact sequences of abelian groups up to homotopy''.



      One can be more ambitious here. Not only $BO$ is an abelian group up to homotopy, but it is an $infty$-loop space, i.e. $BO=Omega^infty bo$ for a certain connective spectrum $bo$. The same applies to $BSO$, $BSpin$,etc., and it also applies to $K(mathbbZ/2mathbbZ,n)$ as $K(mathbbZ/2mathbbZ,n)=Omega^inftySigma^n HmathbbZ/2$. So one may hope that the above sequences are actually infinitely deloopable and come from fibrations
      $$
      bso to boxrightarrowOmega^-inftyw_1 Sigma HmathbbZ/2
      $$

      and
      $$
      bspin to bsoxrightarrowOmega^-inftyw_2 Sigma^2 HmathbbZ/2
      $$

      of connective spectra. Versions of this latter statement seem to appear in the literature, at least in the form "$BSO to BOxrightarroww_1 K(mathbbZ/2mathbbZ,1)$ is a fibration of infinite loop spaces" which however I am only able to give a precise meaning by interpreting it as above. For instance one finds: "Recall that $BSpin^c$ participates in a fibration of infinite loop spaces $K(mathbbZ,2)to BSpin^cto BSOxrightarrowbw_2K(mathbbZ,3)$'' in section 7 of Ando-Blumberg-Gepner's Twists of K-theory and TMF.



      My question is:



      • Is it true that the above are indeed fibrations of connective spectra inducing the usual fibrations of topological spaces via $Omega^infty$?


      • Where can I find a rigorous proof of this statement?







      at.algebraic-topology loop-spaces






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Sep 27 at 21:37









      domenico fiorenzadomenico fiorenza

      5,33518 silver badges35 bronze badges




      5,33518 silver badges35 bronze badges























          2 Answers
          2






          active

          oldest

          votes


















          11

















          $begingroup$

          Your sequences are all arise in the following standard way. Suppose $x$ is an $(n-1)$--connected spectrum and let $X = Omega^infty x$. One always has a
          fibration sequence
          $$y rightarrow x rightarrow Sigma^n Hpi_n(X)$$
          and applying $Omega^infty$ to this yields a fibration sequence of spaces
          $$Y rightarrow X rightarrow K(pi_n(X),n).$$



          $Y$ is the $n$--connected cover of $X$.



          (In your situation, one has successive covers $bspin rightarrow bso rightarrow bo$.)






          share|cite|improve this answer










          $endgroup$









          • 1




            $begingroup$
            Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
            $endgroup$
            – domenico fiorenza
            Sep 28 at 5:52



















          11

















          $begingroup$

          Yes it is true. You have correctly interpreted the intended meaning of the phrase ``fibration of infinite loop spaces''. One early reference is chapter I of $E_infty$ ring spaces and $E_infty$ ring spectra, available at http://www.math.uchicago.edu/~may/BOOKS/e_infty.pdf






          share|cite|improve this answer










          $endgroup$















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            2 Answers
            2






            active

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            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            11

















            $begingroup$

            Your sequences are all arise in the following standard way. Suppose $x$ is an $(n-1)$--connected spectrum and let $X = Omega^infty x$. One always has a
            fibration sequence
            $$y rightarrow x rightarrow Sigma^n Hpi_n(X)$$
            and applying $Omega^infty$ to this yields a fibration sequence of spaces
            $$Y rightarrow X rightarrow K(pi_n(X),n).$$



            $Y$ is the $n$--connected cover of $X$.



            (In your situation, one has successive covers $bspin rightarrow bso rightarrow bo$.)






            share|cite|improve this answer










            $endgroup$









            • 1




              $begingroup$
              Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
              $endgroup$
              – domenico fiorenza
              Sep 28 at 5:52
















            11

















            $begingroup$

            Your sequences are all arise in the following standard way. Suppose $x$ is an $(n-1)$--connected spectrum and let $X = Omega^infty x$. One always has a
            fibration sequence
            $$y rightarrow x rightarrow Sigma^n Hpi_n(X)$$
            and applying $Omega^infty$ to this yields a fibration sequence of spaces
            $$Y rightarrow X rightarrow K(pi_n(X),n).$$



            $Y$ is the $n$--connected cover of $X$.



            (In your situation, one has successive covers $bspin rightarrow bso rightarrow bo$.)






            share|cite|improve this answer










            $endgroup$









            • 1




              $begingroup$
              Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
              $endgroup$
              – domenico fiorenza
              Sep 28 at 5:52














            11















            11











            11







            $begingroup$

            Your sequences are all arise in the following standard way. Suppose $x$ is an $(n-1)$--connected spectrum and let $X = Omega^infty x$. One always has a
            fibration sequence
            $$y rightarrow x rightarrow Sigma^n Hpi_n(X)$$
            and applying $Omega^infty$ to this yields a fibration sequence of spaces
            $$Y rightarrow X rightarrow K(pi_n(X),n).$$



            $Y$ is the $n$--connected cover of $X$.



            (In your situation, one has successive covers $bspin rightarrow bso rightarrow bo$.)






            share|cite|improve this answer










            $endgroup$



            Your sequences are all arise in the following standard way. Suppose $x$ is an $(n-1)$--connected spectrum and let $X = Omega^infty x$. One always has a
            fibration sequence
            $$y rightarrow x rightarrow Sigma^n Hpi_n(X)$$
            and applying $Omega^infty$ to this yields a fibration sequence of spaces
            $$Y rightarrow X rightarrow K(pi_n(X),n).$$



            $Y$ is the $n$--connected cover of $X$.



            (In your situation, one has successive covers $bspin rightarrow bso rightarrow bo$.)







            share|cite|improve this answer













            share|cite|improve this answer




            share|cite|improve this answer










            answered Sep 28 at 3:30









            Nicholas KuhnNicholas Kuhn

            5,23013 silver badges29 bronze badges




            5,23013 silver badges29 bronze badges










            • 1




              $begingroup$
              Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
              $endgroup$
              – domenico fiorenza
              Sep 28 at 5:52













            • 1




              $begingroup$
              Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
              $endgroup$
              – domenico fiorenza
              Sep 28 at 5:52








            1




            1




            $begingroup$
            Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
            $endgroup$
            – domenico fiorenza
            Sep 28 at 5:52





            $begingroup$
            Ah, sure! For any spectrum $x$ one has the fiber sequence $x_>n to x to x_leq n$ given by the standard ($n$-connected,$n$-truncated) $t$-structure on spectra. If $x$ is $(n-1)$-connected then $x_leq n=Sigma^n Hpi_n(x) = Sigma^n Hpi_n(Omega^infty x)$. Then one applies $Omega^infty$. I was missing the obvious here.
            $endgroup$
            – domenico fiorenza
            Sep 28 at 5:52












            11

















            $begingroup$

            Yes it is true. You have correctly interpreted the intended meaning of the phrase ``fibration of infinite loop spaces''. One early reference is chapter I of $E_infty$ ring spaces and $E_infty$ ring spectra, available at http://www.math.uchicago.edu/~may/BOOKS/e_infty.pdf






            share|cite|improve this answer










            $endgroup$


















              11

















              $begingroup$

              Yes it is true. You have correctly interpreted the intended meaning of the phrase ``fibration of infinite loop spaces''. One early reference is chapter I of $E_infty$ ring spaces and $E_infty$ ring spectra, available at http://www.math.uchicago.edu/~may/BOOKS/e_infty.pdf






              share|cite|improve this answer










              $endgroup$
















                11















                11











                11







                $begingroup$

                Yes it is true. You have correctly interpreted the intended meaning of the phrase ``fibration of infinite loop spaces''. One early reference is chapter I of $E_infty$ ring spaces and $E_infty$ ring spectra, available at http://www.math.uchicago.edu/~may/BOOKS/e_infty.pdf






                share|cite|improve this answer










                $endgroup$



                Yes it is true. You have correctly interpreted the intended meaning of the phrase ``fibration of infinite loop spaces''. One early reference is chapter I of $E_infty$ ring spaces and $E_infty$ ring spectra, available at http://www.math.uchicago.edu/~may/BOOKS/e_infty.pdf







                share|cite|improve this answer













                share|cite|improve this answer




                share|cite|improve this answer










                answered Sep 28 at 3:11









                Peter MayPeter May

                26.1k3 gold badges79 silver badges121 bronze badges




                26.1k3 gold badges79 silver badges121 bronze badges































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