3 research outputs found
On the lifting of the Nagata automorphism
It is proved that the Nagata automorphism (Nagata coordinates, respectively)
of the polynomial algebra over a field cannot be lifted to a
-automorphism (-coordinate, respectively) of the free associative algebra
. The proof is based on the following two new results which have
their own interests: degree estimate of and tameness of
the automorphism group .Comment: 15 page