
 Structure Operations (Site not responding. Last check: 20071026) 
  The main structure related to a polynomial ring is its coefficient ring. 
  Given a polynomial ring P=R[x_1,..., x_n] of rank n with coefficient ring R, together with a ring S, construct the polynomial ring Q=S[x_1,..., x_n]. 
  In its general form a ring homomorphism taking a polynomial ring R[x_1,..., x_n] as domain requires n + 1 pieces of information, namely, a map (homomorphism) telling how to map the coefficient ring R together with the images of the n indeterminates. 
 www.umich.edu /~gpcc/scs/magma/text593.htm (369 words) 
