#### D.2.11.4 defring

Procedure from library `ring.lib` (see ring_lib).

Usage:
  defring(ch,n,va,or); ch,va,or=strings, n=integer

Return:
  ring R with characteristic 'ch', ordering 'or' and n variables with names derived from va.
  If va is a single letter, say va="a", and if n<=26 then a and the following n-1 letters from the alphabet (cyclic order) are taken as variables. If n>26 or if va is a single letter followed by a bracket, say va="T(", the variables are T(1),...,T(n).

Note:
  This proc is useful for defining a ring in a procedure. This proc uses 'execute' or calls a procedure using 'execute'.

Example:

    LIB "ring.lib";
    def r=defring("0",5,"u","ls"); r; setring r;"";
    ==> //   characteristic : 0
    ==> //   number of vars : 5
    ==> //        block   1 : ordering ls
    ==> //                  : names    u v w x y
    ==> //        block   2 : ordering C
    ==>
    def R=defring("2,A",10,"x(","dp(3),ws(1,2,3),ds"); R; setring R;
    ==> //   characteristic : 2
    ==> //   1 parameter    : A
    ==> //   minpoly        : 0
    ==> //   number of vars : 10
    ==> //        block   1 : ordering dp
    ==> //                  : names    x(1) x(2) x(3)
    ==> //        block   2 : ordering ws
    ==> //                  : names    x(4) x(5) x(6)
    ==> //                  : weights     1    2    3
    ==> //        block   3 : ordering ds
    ==> //                  : names    x(7) x(8) x(9) x(10)
    ==> //        block   4 : ordering C
    kill R,r;

User manual for Singular version 4-0-3, 2016, generated by texi2html.