-- -*- M2-comint -*- hash: 14358960816422788721

i1 : R = QQ[x,y,z,w]

o1 = R

o1 : PolynomialRing

i2 : P = ideal"xz-y2,yw-z2,xw-yz"; -- The twisted cubic curve

o2 : Ideal of R

i3 : isWellDefined R_P

o3 = true

i4 : Q = ideal"xz-y2,z(yw-z2)-w(xw-yz)";

o4 : Ideal of R

i5 : isWellDefined R_Q

o5 = false

i6 : 
