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IntegralClosure :: isNormal

isNormal -- determine if a reduced ring is normal



This function computes the jacobian of the ring which can be costly for larger rings. Therefore it checks the less costly S2 condition first and if true, then tests the R1 condition using the jacobian of R.

i1 : R = QQ[x,y,z]/ideal(x^6-z^6-y^2*z^4);
i2 : isNormal R

o2 = false
i3 : isNormal(integralClosure R)

o3 = true


The ring R must be an equidimensional ring. If R is a domain, then sometimes computing the integral closure of R can be faster than this test.

See also

Ways to use isNormal :