Skip to main content
Log in

On genus and cancellation in homotopy

  • Published:
Israel Journal of Mathematics Aims and scope Submit manuscript

Abstract

Thegenus is determined for spaces of the homotopy type of aCW complex with one cell each in dimensions 0, 2n and 4n (and no other cells), such spaces providing the only cases of spaces with two non-trivial cells such that the homotopy class of the attaching map for the top cell is of infinite order and the genus of the space is non-trivial. The genus is characterised completely by two well understood invariants: theHopf invariant of the attaching map of the 4n-cell and the genus of thesuspension of the space. The algebraic tools are developed for the investigation of the ν-cancellation behaviour of these spaces and a cancellation theorem is proved: the homotopy type of a finite wedge of such spaces determines the homotopy type of each of the summands as long as the attaching maps of the 4n-cells all represent homotopy classes of infinite order. Comparing this result to known results aboutfinite co-H-spaces shows that the Hopf invariant is the single obstruction to such spaces admitting a co-H structure.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. J. F. Adams,On the non-existence of elements of Hopf invariant one, Ann. of Math.72 (1960), 20–104.

    Article  MathSciNet  Google Scholar 

  2. A. K. Bousfield and D. M. Kan,Homotopy Limits, Completions and Localisations, Lecture Notes in Math.304, Springer-Verlag, Berlin, 1972.

    Google Scholar 

  3. P. Freyd,Stable Homotopy II, AMS Proc. Symp. Pure Math.18 (1970), 161–183.

    MathSciNet  Google Scholar 

  4. P. J. Hilton,Homotopy Theory and Duality, Gordon and Breach, London, 1965.

    Google Scholar 

  5. P. J. Hilton,The Grothendieck group of compact polyhedra, Fund. Math.61 (1967), 199–214.

    MATH  MathSciNet  Google Scholar 

  6. P. J. Hilton, G. Mislin, and J. Roitberg,Localisation of Nilpotent Groups and Spaces, Mathematical Studies No. 15, North-Holland, Amsterdam, 1975.

    Google Scholar 

  7. P. J. Hilton (with M. R. Pfenniger),Nilpotente Gruppen und nilpotente Räume, Lecture Notes in Math.1053, Springer-Verlag, Berlin, 1984.

    MATH  Google Scholar 

  8. E. Molnar,Relation between wedge cancellation and localisation for complexes with two cells, J. Pure Appl. Algebra3 (1972), 77–81.

    MathSciNet  Google Scholar 

  9. G. W. Whitehead,Elements of Homotopy Theory, GTM No. 61, Springer, New York, 1978.

    MATH  Google Scholar 

  10. C. Wilkerson,Genus and cancellation, Topology14 (1975), 29–36.

    Article  MATH  MathSciNet  Google Scholar 

  11. A. Zabrodsky,On the genus of finite CW H-spaces, Comment. Math. Helv.49, fasc. 1 (1974), 48–64.

    Article  MATH  MathSciNet  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Bokor, I. On genus and cancellation in homotopy. Israel J. Math. 73, 361–379 (1991). https://doi.org/10.1007/BF02773848

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02773848

Keywords

Navigation