# Running gp in sage how do I access. e.g.. e.j

I am new to sage and I am trying to run the gp interface.

In gp I can define an elliptic curve e and then access j by e.j

? e=ellinit([0,-1,1,0,0]);
? e.j
%2 = -4096/11


Trying to do the same in sage I did

e=gp.ellinit([0,-1,1,0,0])


What is the syntax to return j for this e. e.j does not work nor do variations like gp.e.j that I tried -- I know that j is stored in

e[13]


but I would like to use the syntax (or something close to) e.j, or e.disc, etc that I am used to typing when working directly in gp.

I am probably missing something very simple here. Thank you for any help.

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Does this answer your question? sagemath.org/doc/constructions/elliptic_curves.html –  Amzoti Dec 6 '12 at 21:43
No - I want to access the j that is a member of e i.e e.j -- I don't want to calculate an new E in sage access member E.j_invariant(). –  sopsku Dec 7 '12 at 0:29
@Amzoti I should added that it is not really j that I am interested in. That was just a reproducible example. I want to learn how to use the gp interface in sage to access the member x (i.e. X.x) for an object X in gp. –  sopsku Dec 7 '12 at 0:34