northcity4's profile - activity

Hi, I am pretty new to SAGE and and am not understanding why my code keeps giving me the error 'RelativeOrder_with_category' object has no attribute 'intersection'. Here is my code:

sage: P1=x^3-x^2-4*x-1
sage: P2=x^3+x^2-2*x-1
sage: K1.<p>=NumberField(P1)
sage: K2.<d>=NumberField(P2)
sage: K.<p,d>=ExtensionField(K1,P2)
sage: O_K=K.ring_of_integers()
sage: A_K1=O_K.intersection(K1)
AttributeError: 'RelativeOrder_with_category' object has no attribute 'intersection'

I have looked at a lot of examples from other questions, but I can't seem to find a solution.