Reference request: mod 2 cohomology of periodic KO theorySingular complex = cohomology ring + Steenrod operations?Homology-Cohomology PairingSteenrod algebra at a prime powerCohomology of the Image of J spectrumThe Segal Machine constructing spectra and topological $K$-TheoryEndomorphism ring spectrum of the Eilenberg-MacLane spectrumRealizing $mathcalA(2)//mathcalA(1)$ by a finite spectrumCohomology of $ko,tmf,MSpin,MString$ with coefficients $mathbbZ/p$ for odd primes $p$The connective $k$-theory cohomology of Eilenberg-MacLane spectraMaps from mod-$p$ Eilenberg-MacLane spectrum to connective $K$-theory spectrum

Reference request: mod 2 cohomology of periodic KO theory


Singular complex = cohomology ring + Steenrod operations?Homology-Cohomology PairingSteenrod algebra at a prime powerCohomology of the Image of J spectrumThe Segal Machine constructing spectra and topological $K$-TheoryEndomorphism ring spectrum of the Eilenberg-MacLane spectrumRealizing $mathcalA(2)//mathcalA(1)$ by a finite spectrumCohomology of $ko,tmf,MSpin,MString$ with coefficients $mathbbZ/p$ for odd primes $p$The connective $k$-theory cohomology of Eilenberg-MacLane spectraMaps from mod-$p$ Eilenberg-MacLane spectrum to connective $K$-theory spectrum













5












$begingroup$


The mod 2 cohomology of the connective ko spectrum is known to be the module $mathcalAotimes_mathcalA_2 mathbbF_2$, where $mathcalA$ denotes the Steenrod algebra, and $mathcalA_2$ denotes the subalgebra generated by $Sq^1$ and $Sq^2$.



Where can I find the original calculation for referencing it ?
What is the structure as module over the steenrod algebra of the mod 2 cohomology of periodic KO theory?










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$endgroup$







  • 1




    $begingroup$
    Unless I'm mistaken $pi_*(HmathbbF_2wedge KO)=0$ (it is a ring of positive characteristic containing an isomorphism between the additive and the multiplicative formal group law), so the answer to your second question is rather trivial
    $endgroup$
    – Denis Nardin
    7 hours ago











  • $begingroup$
    Indeed, as the periodicity generator ie the Bott element induces zero-map in ordinary homology!
    $endgroup$
    – Prasit
    7 hours ago






  • 1




    $begingroup$
    It is more usual to use $mathcalA_1$ to denote the algebra generated by $mathrmSq^1$ and $mathrmSq^2$.
    $endgroup$
    – John Palmieri
    4 hours ago















5












$begingroup$


The mod 2 cohomology of the connective ko spectrum is known to be the module $mathcalAotimes_mathcalA_2 mathbbF_2$, where $mathcalA$ denotes the Steenrod algebra, and $mathcalA_2$ denotes the subalgebra generated by $Sq^1$ and $Sq^2$.



Where can I find the original calculation for referencing it ?
What is the structure as module over the steenrod algebra of the mod 2 cohomology of periodic KO theory?










share|cite|improve this question









$endgroup$







  • 1




    $begingroup$
    Unless I'm mistaken $pi_*(HmathbbF_2wedge KO)=0$ (it is a ring of positive characteristic containing an isomorphism between the additive and the multiplicative formal group law), so the answer to your second question is rather trivial
    $endgroup$
    – Denis Nardin
    7 hours ago











  • $begingroup$
    Indeed, as the periodicity generator ie the Bott element induces zero-map in ordinary homology!
    $endgroup$
    – Prasit
    7 hours ago






  • 1




    $begingroup$
    It is more usual to use $mathcalA_1$ to denote the algebra generated by $mathrmSq^1$ and $mathrmSq^2$.
    $endgroup$
    – John Palmieri
    4 hours ago













5












5








5


1



$begingroup$


The mod 2 cohomology of the connective ko spectrum is known to be the module $mathcalAotimes_mathcalA_2 mathbbF_2$, where $mathcalA$ denotes the Steenrod algebra, and $mathcalA_2$ denotes the subalgebra generated by $Sq^1$ and $Sq^2$.



Where can I find the original calculation for referencing it ?
What is the structure as module over the steenrod algebra of the mod 2 cohomology of periodic KO theory?










share|cite|improve this question









$endgroup$




The mod 2 cohomology of the connective ko spectrum is known to be the module $mathcalAotimes_mathcalA_2 mathbbF_2$, where $mathcalA$ denotes the Steenrod algebra, and $mathcalA_2$ denotes the subalgebra generated by $Sq^1$ and $Sq^2$.



Where can I find the original calculation for referencing it ?
What is the structure as module over the steenrod algebra of the mod 2 cohomology of periodic KO theory?







at.algebraic-topology kt.k-theory-and-homology stable-homotopy






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share|cite|improve this question











share|cite|improve this question




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asked 8 hours ago









Nicolas BoergerNicolas Boerger

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9995 silver badges13 bronze badges







  • 1




    $begingroup$
    Unless I'm mistaken $pi_*(HmathbbF_2wedge KO)=0$ (it is a ring of positive characteristic containing an isomorphism between the additive and the multiplicative formal group law), so the answer to your second question is rather trivial
    $endgroup$
    – Denis Nardin
    7 hours ago











  • $begingroup$
    Indeed, as the periodicity generator ie the Bott element induces zero-map in ordinary homology!
    $endgroup$
    – Prasit
    7 hours ago






  • 1




    $begingroup$
    It is more usual to use $mathcalA_1$ to denote the algebra generated by $mathrmSq^1$ and $mathrmSq^2$.
    $endgroup$
    – John Palmieri
    4 hours ago












  • 1




    $begingroup$
    Unless I'm mistaken $pi_*(HmathbbF_2wedge KO)=0$ (it is a ring of positive characteristic containing an isomorphism between the additive and the multiplicative formal group law), so the answer to your second question is rather trivial
    $endgroup$
    – Denis Nardin
    7 hours ago











  • $begingroup$
    Indeed, as the periodicity generator ie the Bott element induces zero-map in ordinary homology!
    $endgroup$
    – Prasit
    7 hours ago






  • 1




    $begingroup$
    It is more usual to use $mathcalA_1$ to denote the algebra generated by $mathrmSq^1$ and $mathrmSq^2$.
    $endgroup$
    – John Palmieri
    4 hours ago







1




1




$begingroup$
Unless I'm mistaken $pi_*(HmathbbF_2wedge KO)=0$ (it is a ring of positive characteristic containing an isomorphism between the additive and the multiplicative formal group law), so the answer to your second question is rather trivial
$endgroup$
– Denis Nardin
7 hours ago





$begingroup$
Unless I'm mistaken $pi_*(HmathbbF_2wedge KO)=0$ (it is a ring of positive characteristic containing an isomorphism between the additive and the multiplicative formal group law), so the answer to your second question is rather trivial
$endgroup$
– Denis Nardin
7 hours ago













$begingroup$
Indeed, as the periodicity generator ie the Bott element induces zero-map in ordinary homology!
$endgroup$
– Prasit
7 hours ago




$begingroup$
Indeed, as the periodicity generator ie the Bott element induces zero-map in ordinary homology!
$endgroup$
– Prasit
7 hours ago




1




1




$begingroup$
It is more usual to use $mathcalA_1$ to denote the algebra generated by $mathrmSq^1$ and $mathrmSq^2$.
$endgroup$
– John Palmieri
4 hours ago




$begingroup$
It is more usual to use $mathcalA_1$ to denote the algebra generated by $mathrmSq^1$ and $mathrmSq^2$.
$endgroup$
– John Palmieri
4 hours ago










1 Answer
1






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7












$begingroup$

Ravenel in his Complex Cobordism and Stable Homotopy Groups of Spheres attributes this result to Stong, in Determination of $H^*(BO(k,⋯,∞),Z_2)$ and $H^∗(BU(k,⋯,∞),Z_2)$, but looking at that paper (which is concerned mainly with the "unstable" cohomology of the various constituent spaces of $ko$), he attributes this further to




Adams, J. F., On Chern characters and the structure of the unitary group, Proc. Camb. Philos. Soc. 57, 189-199 (1961). ZBL0103.16001.




There you can find indeed the required result as Lemma 4.



Regarding your second question, the cohomology $H^*(KO;mathbbF_2)$ is zero for chromatic reasons (the spectrum $KUwedge HmathbbF_2$ carries an isomorphism of the additive and multiplicative formal group law in characteristic two, so it must be trivial, and then you can use the fact that $KU=KO/eta$ to conclude, since $eta$ is nilpotent in $pi_*KO$), hence the map $H^*(KO;mathbbF_2)→H^*(ko;mathbbF_2)$ is trivial.






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    7












    $begingroup$

    Ravenel in his Complex Cobordism and Stable Homotopy Groups of Spheres attributes this result to Stong, in Determination of $H^*(BO(k,⋯,∞),Z_2)$ and $H^∗(BU(k,⋯,∞),Z_2)$, but looking at that paper (which is concerned mainly with the "unstable" cohomology of the various constituent spaces of $ko$), he attributes this further to




    Adams, J. F., On Chern characters and the structure of the unitary group, Proc. Camb. Philos. Soc. 57, 189-199 (1961). ZBL0103.16001.




    There you can find indeed the required result as Lemma 4.



    Regarding your second question, the cohomology $H^*(KO;mathbbF_2)$ is zero for chromatic reasons (the spectrum $KUwedge HmathbbF_2$ carries an isomorphism of the additive and multiplicative formal group law in characteristic two, so it must be trivial, and then you can use the fact that $KU=KO/eta$ to conclude, since $eta$ is nilpotent in $pi_*KO$), hence the map $H^*(KO;mathbbF_2)→H^*(ko;mathbbF_2)$ is trivial.






    share|cite|improve this answer











    $endgroup$

















      7












      $begingroup$

      Ravenel in his Complex Cobordism and Stable Homotopy Groups of Spheres attributes this result to Stong, in Determination of $H^*(BO(k,⋯,∞),Z_2)$ and $H^∗(BU(k,⋯,∞),Z_2)$, but looking at that paper (which is concerned mainly with the "unstable" cohomology of the various constituent spaces of $ko$), he attributes this further to




      Adams, J. F., On Chern characters and the structure of the unitary group, Proc. Camb. Philos. Soc. 57, 189-199 (1961). ZBL0103.16001.




      There you can find indeed the required result as Lemma 4.



      Regarding your second question, the cohomology $H^*(KO;mathbbF_2)$ is zero for chromatic reasons (the spectrum $KUwedge HmathbbF_2$ carries an isomorphism of the additive and multiplicative formal group law in characteristic two, so it must be trivial, and then you can use the fact that $KU=KO/eta$ to conclude, since $eta$ is nilpotent in $pi_*KO$), hence the map $H^*(KO;mathbbF_2)→H^*(ko;mathbbF_2)$ is trivial.






      share|cite|improve this answer











      $endgroup$















        7












        7








        7





        $begingroup$

        Ravenel in his Complex Cobordism and Stable Homotopy Groups of Spheres attributes this result to Stong, in Determination of $H^*(BO(k,⋯,∞),Z_2)$ and $H^∗(BU(k,⋯,∞),Z_2)$, but looking at that paper (which is concerned mainly with the "unstable" cohomology of the various constituent spaces of $ko$), he attributes this further to




        Adams, J. F., On Chern characters and the structure of the unitary group, Proc. Camb. Philos. Soc. 57, 189-199 (1961). ZBL0103.16001.




        There you can find indeed the required result as Lemma 4.



        Regarding your second question, the cohomology $H^*(KO;mathbbF_2)$ is zero for chromatic reasons (the spectrum $KUwedge HmathbbF_2$ carries an isomorphism of the additive and multiplicative formal group law in characteristic two, so it must be trivial, and then you can use the fact that $KU=KO/eta$ to conclude, since $eta$ is nilpotent in $pi_*KO$), hence the map $H^*(KO;mathbbF_2)→H^*(ko;mathbbF_2)$ is trivial.






        share|cite|improve this answer











        $endgroup$



        Ravenel in his Complex Cobordism and Stable Homotopy Groups of Spheres attributes this result to Stong, in Determination of $H^*(BO(k,⋯,∞),Z_2)$ and $H^∗(BU(k,⋯,∞),Z_2)$, but looking at that paper (which is concerned mainly with the "unstable" cohomology of the various constituent spaces of $ko$), he attributes this further to




        Adams, J. F., On Chern characters and the structure of the unitary group, Proc. Camb. Philos. Soc. 57, 189-199 (1961). ZBL0103.16001.




        There you can find indeed the required result as Lemma 4.



        Regarding your second question, the cohomology $H^*(KO;mathbbF_2)$ is zero for chromatic reasons (the spectrum $KUwedge HmathbbF_2$ carries an isomorphism of the additive and multiplicative formal group law in characteristic two, so it must be trivial, and then you can use the fact that $KU=KO/eta$ to conclude, since $eta$ is nilpotent in $pi_*KO$), hence the map $H^*(KO;mathbbF_2)→H^*(ko;mathbbF_2)$ is trivial.







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited 7 hours ago

























        answered 7 hours ago









        Denis NardinDenis Nardin

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