The Z-Classes of Isometries

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Authors

  • Department of Mathematical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Punjab 140 306 ,IN
  • Bhaskaracharya Pratishthana, 56/14, Erandavane, Damle Path, Pune 411 004 ,IN

Keywords:

Conjugacy Classes, Centralizers, Z-Classes, Orthogonal and Symplectic Groups.

Abstract

Let G be a group. Two elements x, y are said to be in the same z-class if their centralizers are conjugate in G. Let V be a vector space of dimension n over a field F of characteristic different from 2. Let B be a non-degenerate symmetric, or skew-symmetric, bilinear form on V. Let I(V,B) denote the group of isometries of (V,B). We show that the number of z-classes in I(V,B) is finite when F is perfect and has the property that it has only finitely many field extensions of degree at most n.