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IsSigmaGoodPrime

check if INT is good primt for IDEAL

Syntax
IsSigmaGoodPrime(p: INT, I: IDEAL): BOOL

Description
This function checks if p is a sigma-good prime for I , that is if it is good for modular reduction of the sigma-reduced GBasis of I .

See article Abbott, Bigatti, Robbiano "Ideals modulo p" ( https://arxiv.org/abs/1801.06112 )

Example
/**/ use QQ[x,y,z];
/**/ I := ideal(2*x*y^2 -1, 3*x^3*y -1);
/**/ ReducedGBasis(I);
[x*y^2 -1/2,  x^2 +(-2/3)*y,  y^3 +(-3/4)*x]
/**/ DenSigma(I);
12
/**/ IsSigmaGoodPrime(2,I);
false
/**/ IsSigmaGoodPrime(32003,I);
true

See Also