#4749: improve coercion of points between elliptic curves and reduction of 
points
mod p
---------------------------+------------------------------------------------
 Reporter:  was            |       Owner:  was       
     Type:  enhancement    |      Status:  new       
 Priority:  major          |   Milestone:  sage-3.2.2
Component:  number theory  |    Keywords:            
---------------------------+------------------------------------------------
 If I have a point P on an elliptic curve E and F is another curve, then
 F(P) should work if possible.  It doesn't.   For example:
 {{{
 E = EllipticCurve([1,-1,0,94,9])
 R = E([0,3]) + 5*E([8,31])      # big denom's
 E11 = E.change_ring(GF(11))
 E11(R)
  BOOM!
 }}}
 But it should clear denominators and coerce in the triple like so:
 {{{
 def reduce(R, p):
     x, y = R.xy()
     d = LCM(x.denominator(), y.denominator())
     return R.curve().change_ring(GF(p))([x*d,y*d,d])
 }}}
 }}}

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/4749>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of 
Reinventing the Wheel
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