Bijective PC-maps of the unipotent radical of the Borel subgroup of the classical symplectic group.

We classify the commutator preserving bijections of the unipotent radical U p (2 n , F) of the Borel subgroup of the classical symplectic group of rank at least 2 over a field F such that 6F=F. Every such a bijection is shown to be the composition of a standard automorphism of U p (2 n , F) and a central map. The latter is the identity modulo the centre of U p (2 n , F). [ABSTRACT FROM AUTHOR]