Topics in Geometric Group Theory, Chicago Lectures in Mathematics
- P. de la Harpe
- Univ. of Chicago Press, Chicago,
Let R be a commutative integral domain of characteristic 0, and let G be a finite subgroup of PGLn(R), the projective general linear group of degree n over R. In this note, we show that if n ≥ 2, then PGLn(R) also contains the free product G ∗ T , where T is the infinite cyclic group generated by the image of a suitable transvection.