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7.10.3.2 lpIsSemiPrime
Procedure from library fpaprops.lib (see fpaprops_lib).
- Usage:
- lpIsSemiPrime(G); G an ideal in a Letterplace ring
- Return:
- boolean
- Purpose:
- Check whether A/<LM(G)> is semi-prime ring,
alternatively whether <LM(G)> is a semi-prime ideal in A.
- Assume:
- - basering is a Letterplace ring
- G is a Groebner basis
- Theory:
- A (two-sided) ideal I in the ring A is semi-prime, if for any a in A one has
aAa subseteq I implies a in I.
- Note:
- lpIsSemiPrime works with the monomial algebra A/<LM(G)>.
A positive answer holds for both A/<LM(G)> and A/<G>, while
a negative answer applies only to A/<LM(G)> and not necessarily to
A/<G>.
Example:
| LIB "fpaprops.lib";
ring r = 0,(x1,x2),dp;
def R = freeAlgebra(r, 5);
setring R;
ideal G = x1*x2, x2*x1; // K<x1,x2>/<x1*x2,x2*x1> is semi prime
lpIsSemiPrime(G);
==> 1
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