#13619: Enable polynomial content over padic fields
---------------------------+------------------------------------------------
   Reporter:  saraedum     |             Owner:  roed    
       Type:  enhancement  |            Status:  new     
   Priority:  trivial      |         Milestone:  sage-5.5
  Component:  padics       |          Keywords:          
Work issues:               |   Report Upstream:  N/A     
  Reviewers:               |           Authors:          
  Merged in:               |      Dependencies:          
   Stopgaps:               |  
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 Currently, one cannot call {{{content()}}} for a polynomial defined over
 {{{Qp}}}:
 {{{
 sage: K = Qp(3)
 sage: R.<t> = K[]
 sage: t.content()
 TypeError: ground ring is a field.  Answer is only defined up to units.
 }}}

 The intention is apparently to protect the user from calling
 {{{content()}}} if he mistakenly got from {{{Zp}}} into {{{Qp}}}, since
 the content there would be always zero or one. However, this can be
 annoying when writing algorithms which work over {{{Zp}}} and {{{Qp}}} but
 which have to take the content into account over {{{Zp}}}.

 Additionally, the content shows a somewhat strange behaviour for zero
 polynomials::
 {{{
 sage: R = Zp(3)
 sage: S.<t> = R[]
 sage: f = S(R(0,3)); f
 (O(3^3))
 sage: f.is_zero()
 True
 sage: f.content()
 3 + O(3^23)
 sage: _.is_zero()
 False
 }}}

 I don't think that the current behaviour is mathematically incorrect, but
 I believe it's not very intuitive.

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13619>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
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