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2.5.1 qring declaration

Syntax:
qring name = ideal_expression ;
Default:
none
Purpose:
declares a quotient ring as the basering modulo ideal_expression. Sets it as current basering.
Example:
 
ring r=0,(x,y,z,u,v,w),dp;
ncalgebra(-1,0);
// anticommutative algebra
option(redSB);
option(redTail);
ideal i=x^2,y^2,z^2,u^2,v^2,w^2;
qring q=twostd(i);
// now it is an exterior algebra
q;
==> //   characteristic : 0
==> //   number of vars : 6
==> //        block   1 : ordering dp
==> //                  : names    x y z u v w 
==> //        block   2 : ordering C
==> //   noncommutative relations:
==> //    yx=-xy
==> //    zx=-xz
==> //    ux=-xu
==> //    vx=-xv
==> //    wx=-xw
==> //    zy=-yz
==> //    uy=-yu
==> //    vy=-yv
==> //    wy=-yw
==> //    uz=-zu
==> //    vz=-zv
==> //    wz=-zw
==> //    vu=-uv
==> //    wu=-uw
==> //    wv=-vw
==> // quotient ring from ideal
==> _[1]=w2
==> _[2]=v2
==> _[3]=u2
==> _[4]=z2
==> _[5]=y2
==> _[6]=x2
poly k=(x+y)*(y-u)*(zv+u-w);
k;
==> xyzv+y2zv+xzuv+yzuv+xyu+y2u-xu2-yu2-xyw-y2w+xuw+yuw
poly ek=reduce(k,std(0));
ek;
==> xyzv+xzuv+yzuv+xyu-xyw+xuw+yuw


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            User manual for Singular version 2-1-99, August 2004, generated by texi2html.