2026/02/10 by M. Archita, Karim Johannes Becher
Mathematics · #math.RA #math.AG #math.NT
We show that the group of proper projective similitudes of a totally decomposable algebra with orthogonal or symplectic involution of index at most 2 over a field of characteristic different from 2 is R-trivial. We further give an example showing that the statement does not extend to index 4 in the orthogonal case.