No CrossRef data available.
Published online by Cambridge University Press: 16 February 2012
An endomorphism φ of a polynomial ring is said to preserve outer rank if φ sends each polynomial to one with the same outer rank. For the polynomial ring in two variables over a field of characteristic 0 we prove that an endomorphism φ preserving outer rank is an automorphism if one of the following conditions holds: (1) the Jacobian of φ is a nonzero constant; (2) the image of φ contains a coordinate; (3) φ has a ‘fixed point’.
Supported by NSF of China (No.11071097) and ‘211 Project’ and ‘985 Project’ of Jilin University.