Home Inertia groups and smooth structures on quaternionic projective spaces
Article
Licensed
Unlicensed Requires Authentication

Inertia groups and smooth structures on quaternionic projective spaces

  • Samik Basu and Ramesh Kasilingam EMAIL logo
Published/Copyright: January 6, 2022

Abstract

This paper deals with certain results on the number of smooth structures on quaternionic projective spaces, obtained through the computation of inertia groups and their analogues, which in turn are computed using techniques from stable homotopy theory. We show that the concordance inertia group is trivial in dimension 20, but there are many examples in high dimensions where the concordance inertia group is non-trivial. We extend these to computations of concordance classes of smooth structures. These have applications to 3-sphere actions on homotopy spheres and tangential homotopy structures.


Communicated by Jan Bruinier


Acknowledgements

The research of the first author was partially supported by NBHM (project ref. number 2/48(11)/2015/NBHM(R.P.)/R&D II/3743).

References

[1] C. S. Aravinda and F. T. Farrell, Exotic structures and quaternionic hyperbolic manifolds, Algebraic Groups and Arithmetic, Tata Inst. Fund. Res., Mumbai (2004), 507–524. Search in Google Scholar

[2] S. Basu and R. Kasilingam, Inertia groups of high-dimensional complex projective spaces, Algebr. Geom. Topol. 18 (2018), no. 1, 387–408. 10.2140/agt.2018.18.387Search in Google Scholar

[3] A. Borel, Compact Clifford–Klein forms of symmetric spaces, Topology 2 (1963), 111–122. 10.1016/0040-9383(63)90026-0Search in Google Scholar

[4] W. Browder, Surgery on Simply-Connected Manifolds, Ergeb. Math. Grenzgeb. (3) 65, Springer, New York, 1972. 10.1007/978-3-642-50020-6Search in Google Scholar

[5] G. Brumfiel, Differentiable 𝕊1- Actions on Homotopy Spheres (mimeographed), University of California, Berkeley, 1968. Search in Google Scholar

[6] G. Brumfiel, Homotopy equivalences of almost smooth manifolds, Comment. Math. Helv. 46 (1971), 381–407. 10.1090/pspum/022/0319217Search in Google Scholar

[7] D. Burghelea, Free differentiable S1 and S3 actions on homotopy spheres, Ann. Sci. Éc. Norm. Supér. (4) 5 (1972), 183–215. 10.24033/asens.1224Search in Google Scholar

[8] A. M. Gleason, Spaces with a compact Lie group of transformations, Proc. Amer. Math. Soc. 1 (1950), 35–43. 10.1090/S0002-9939-1950-0033830-7Search in Google Scholar

[9] D. N. Hertz, Ambient surgery and tangential homotopy quaternionic projective spaces, Trans. Amer. Math. Soc. 145 (1969), 517–545. 10.1090/S0002-9947-1969-0250320-6Search in Google Scholar

[10] W.-C. Hsiang, A note on free differentiable actions of S1 and S3 on homotopy spheres, Ann. of Math. (2) 83 (1966), 266–272. 10.2307/1970431Search in Google Scholar

[11] I. M. James, Relative Stiefel Manifolds, London Math. Soc. Lecture Note Ser. 24, Cambridge University, Cambridge, 1976. 10.1112/jlms/s2-13.2.331Search in Google Scholar

[12] I. H. Kaddoura, De-suspension of free S3-actions on homotopy spheres, Int. J. Algebra 6 (2012), no. 17–20, 985–994. Search in Google Scholar

[13] R. Kasilingam, Homotopy inertia groups and tangential structures, JP J. Geom. Topol. 20 (2017), 91–114. 10.17654/GT020020091Search in Google Scholar

[14] K. Kawakubo, Inertia groups of low dimensional complex projective spaces and some free differentiable actions on spheres. I, Proc. Japan Acad. 44 (1968), 873–875. 10.3792/pja/1195520972Search in Google Scholar

[15] K. Kawakubo, On the inertia groups of homology tori, J. Math. Soc. Japan 21 (1969), 37–47. 10.2969/jmsj/02110037Search in Google Scholar

[16] M. A. Kervaire and J. W. Milnor, Groups of homotopy spheres. I, Ann. of Math. (2) 77 (1963), 504–537. 10.1142/9789812836878_0002Search in Google Scholar

[17] R. C. Kirby and L. C. Siebenmann, Foundational Essays on Topological Manifolds, Smoothings, and Triangulations, Ann. of Math. Stud. 88, Princeton University, Princeton, 1977. 10.1515/9781400881505Search in Google Scholar

[18] S. O. Kochman, Bordism, Stable Homotopy and Adams Spectral Sequences, Fields Inst. Monogr. 7, American Mathematical Society, Providence, 1996. 10.1090/fim/007Search in Google Scholar

[19] L. Kramer and S. Stolz, A diffeomorphism classification of manifolds which are like projective planes, J. Differential Geom. 77 (2007), no. 2, 177–188. 10.4310/jdg/1191860392Search in Google Scholar

[20] H.-T. Ku, A note on semifree actions of S1 on homotopy spheres, Proc. Amer. Math. Soc. 22 (1969), 614–617. 10.1090/S0002-9939-1969-0264696-2Search in Google Scholar

[21] H.-T. Ku and M.-C. Ku, Free differentiable actions of S1 and S3 on homotopy spheres, Proc. Amer. Math. Soc. 25 (1970), 864–869. 10.1090/S0002-9939-1970-0264697-2Search in Google Scholar

[22] H.-T. Ku and M.-C. Ku, Characteristic spheres of free differentiable actions of S1 and S3 on homotopy spheres, Trans. Amer. Math. Soc. 156 (1971), 493–504. 10.2307/1995623Search in Google Scholar

[23] N. H. Kuiper and R. K. Lashof, Microbundles and bundles. I. Elementary theory, Invent. Math. 1 (1966), 1–17. 10.1007/BF01389695Search in Google Scholar

[24] R. Lashof and M. Rothenberg, Microbundles and smoothing, Topology 3 (1965), 357–388. 10.1016/0040-9383(65)90003-0Search in Google Scholar

[25] C.-N. Lee, Detection of some elements in the stable homotopy groups of spheres, Math. Z. 222 (1996), no. 2, 231–245. 10.1007/BF02621865Search in Google Scholar

[26] I. Madsen and R. J. Milgram, The Classifying Spaces for Surgery and Cobordism of Manifolds, Ann. of Math. Stud. 92, Princeton University, Princeton, 1979. 10.1515/9781400881475Search in Google Scholar

[27] I. Madsen, L. R. Taylor and B. Williams, Tangential homotopy equivalences, Comment. Math. Helv. 55 (1980), no. 3, 445–484. 10.1007/BF02566699Search in Google Scholar

[28] I. Madsen, C. B. Thomas and C. T. C. Wall, The topological spherical space form problem. II. Existence of free actions, Topology 15 (1976), no. 4, 375–382. 10.1016/0040-9383(76)90031-8Search in Google Scholar

[29] J. Milnor, On manifolds homeomorphic to the 7-sphere, Ann. of Math. (2) 64 (1956), 399–405. 10.1142/9789812836878_0001Search in Google Scholar

[30] R. E. Mosher, Some stable homotopy of complex projective space, Topology 7 (1968), 179–193. 10.1016/0040-9383(68)90026-8Search in Google Scholar

[31] R. E. Mosher and M. C. Tangora, Cohomology Operations and Applications in Homotopy Theory, Harper & Row, New York, 1968. Search in Google Scholar

[32] B. Okun, Exotic smooth structures on nonpositively curved symmetric spaces, Algebr. Geom. Topol. 2 (2002), 381–389. 10.2140/agt.2002.2.381Search in Google Scholar

[33] K. Ramesh, Farrell–Jones spheres and inertia groups of complex projective spaces, Forum Math. 27 (2015), no. 5, 3005–3015. 10.1515/forum-2013-0072Search in Google Scholar

[34] K. Ramesh, Inertia groups and smooth structures of (n-1)-connected 2n-manifolds, Osaka J. Math. 53 (2016), no. 2, 309–319. Search in Google Scholar

[35] D. C. Ravenel, Complex Cobordism and Stable Homotopy Groups of Spheres, 2nd ed., AMS Chelsea, Providence, 2004. 10.1090/chel/347Search in Google Scholar

[36] R. Schultz, On the inertia group of a product of spheres, Trans. Amer. Math. Soc. 156 (1971), 137–153. 10.1090/S0002-9947-1971-0275453-9Search in Google Scholar

[37] R. Schultz, Homology spheres as stationary sets of circle actions, Michigan Math. J. 34 (1987), no. 2, 183–200. 10.1307/mmj/1029003551Search in Google Scholar

[38] F. Sigrist and U. Suter, Cross-sections of symplectic Stiefel manifolds, Trans. Amer. Math. Soc. 184 (1973), 247–259. 10.1090/S0002-9947-1973-0326728-8Search in Google Scholar

[39] D. P. Sullivan, Triangulating and smoothing homotopy equivalences and homeomorphisms, The Hauptvermutung Book, K-Monogr. Math. 1, Kluwer Academic, Dordrecht (1996), 69–103. 10.1007/978-94-017-3343-4_3Search in Google Scholar

[40] I. Tamura, Sur les sommes connexes de certaines variétés différentiables, C. R. Math. Acad. Sci. Paris 255 (1962), 3104–3106. Search in Google Scholar

Received: 2020-05-18
Revised: 2021-11-21
Published Online: 2022-01-06
Published in Print: 2022-03-01

© 2022 Walter de Gruyter GmbH, Berlin/Boston

Downloaded on 10.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/forum-2020-0125/html
Scroll to top button