#7576: improvements to the prove_BSD function
-------------------------------+--------------------------------------------
Reporter: rlm | Owner: cremona
Type: enhancement | Status: needs_work
Priority: major | Milestone: sage-4.3.1
Component: elliptic curves | Keywords:
Work_issues: | Author: Robert Miller
Upstream: N/A | Reviewer:
Merged: |
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Changes (by rlm):
* status: positive_review => needs_work
Comment:
For 438e1 and 960d1, we get:
{{{
RuntimeError Traceback (most recent call
last)
/home/wstein/<ipython console> in <module>()
/home/wstein/sage/local/lib/python2.6/site-
packages/sage/schemes/elliptic_curves/ell_rational_field.pyc
in prove_BSD(self, verbosity, simon, proof, secs_hi)
6372 print 'p = 2: true by 2-descent'
6373 else:
-> 6374 raise RuntimeError("ord2(#Sha) was computed to be
%d, but ord2(#Sha_an) is %d for this curve (%s)! This may be a
counterexample to BSD, but is more likely a
bug."%(sha_ord_2,sha_an.ord(2),self))
6375
6376 # reduce set of remaining primes to a finite set
RuntimeError: ord2(#Sha) was computed to be 1, but ord2(#Sha_an) is 0
for this curve (Elliptic Curve defined by y^2 + x*y + y = x^3 - 130*x
- 556 over Rational Field)! This may be a counterexample to BSD, but
is more likely a bug.
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7576#comment:8>
Sage <http://www.sagemath.org>
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