Fundamental Exact Sequence of Wells

  • Inder Bir Singh PassiEmail author
  • Mahender Singh
  • Manoj Kumar Yadav
Part of the Springer Monographs in Mathematics book series (SMM)


Given a normal subgroup N of a group G, a basic problem in the theory of automorphisms of groups is that of extending an automorphism of N to an automorphism of G, and the analogous one of lifting an automorphism of the quotient group G / N to an automorphism of G. A crucial role in the investigation of these problems is played by an exact sequence due to Wells [126]. In this chapter, a detailed exposition of this sequence and its role in determining conditions for extension and lifting of automorphisms is presented.

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© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  • Inder Bir Singh Passi
    • 1
    Email author
  • Mahender Singh
    • 2
  • Manoj Kumar Yadav
    • 3
  1. 1.Centre for Advanced Study in MathematicsPanjab UniversityChandigarhIndia
  2. 2.Department of Mathematical SciencesIndian Institute of Science Education and Research MohaliSAS NagarIndia
  3. 3.School of MathematicsHarish-Chandra Research Institute HBNIJhunsi AllahabadIndia

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