Overview Objects Functionality Examples Applications	Groebner Bases For Left And Two-sided Ideals - Part1 ideal I2=e^2,f^2,h^2-1; ideal L2=std(I2); L2; ==> L2[1]=h2-1 L2[2]=fh-f L2[3]=f2 L2[4]=eh+e L2[5]=2ef-h2-h L2[6]=e2 ideal T2=system("twostd",I2); T2; ==> T2[1]=h2-1 T2[2]=fh-f T2[3]=f2 T2[4]=eh+e T2[5]=2ef-h2-h T2[6]=e2 This shows that I2 is a two-sided ideal itself. Now let us compute the central character of I2, namely such constant C, that z+C belongs to I2 : poly z=4*e*f+h^2-2*h; poly C=NF(z,L2); C; ==> 3 Back to the parent example
Lille, 08-07-02	http://www.singular.uni-kl.de