I suspect the question might have been referring to elliptic curves over finite fields. In the ordinary case you can ask for the Frobenius order and know that the endomorphism ring is between that and the maximal order of its field of fractions (an imaginary quadratic field) but as far as I know Sage jas no implementation of finding the exact endomorphism ring such as Kohel's algorithm.
-- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/e883d3f6-bbf4-422b-b964-b6f72abb746a%40googlegroups.com.