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7.5.1.0. bistd
Procedure from library bimodules.lib (see bimodules_lib).
- Usage:
- bistd(M); M is (two-sided) ideal/module
- Return:
- ideal or module (same type as the argument)
- Purpose:
- Computes the two-sided Groebner basis of an ideal/module with the help the enveloping algebra of the basering, alternative to twostd() for ideals.
Example:
| | LIB "bimodules.lib";
ring w = 0,(x,s),Dp;
def W=nc_algebra(1,s); // 1st shift algebra
setring W;
matrix m[3][3]=[s^2,s+1,0],[s+1,0,s^3-x^2*s],[2*s+1, s^3+s^2, s^2];
print(m);
==> s2, s+1, s+1,
==> 0, -x2s+s3,2s+1,
==> s3+s2,s2, 0
module L = m; module M2 = bistd(L);
print(M2);
==> 1,1,s+1,
==> 0,1,0,
==> 0,0,s2
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