#11549: Arithmetic with symbolic vectors always creates a new
FreeModuleElement_generic_dense
-------------------------+--------------------------------------------------
   Reporter:  jvkersch   |          Owner:  burcin                      
       Type:  defect     |         Status:  new                         
   Priority:  major      |      Milestone:  sage-4.7.2                  
  Component:  symbolics  |       Keywords:  vector, symbolic, arithmetic
Work_issues:             |       Upstream:  N/A                         
   Reviewer:             |         Author:                              
     Merged:             |   Dependencies:                              
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 Arithmetic with symbolic vectors (addition, scalar multiplication)
 produces an instance of `FreeModuleElement_generic_dense` instead of a new
 symbolic vector:

 {{{
 sage: v = vector(SR, [1])
 sage: w = vector(SR, [x])
 sage: type(v)
 <class 'sage.modules.vector_symbolic_dense.Vector_symbolic_dense'>
 sage: type(w)
 <class 'sage.modules.vector_symbolic_dense.Vector_symbolic_dense'>
 sage: type(v + w)
 <type 'sage.modules.free_module_element.FreeModuleElement_generic_dense'>
 }}}

 As David Roe pointed out, the problem is due to the constructor in
 `FreeModuleElement_generic_dense` hard-coding the class, so that
 arithmetic operations with symbolic vectors ends up being a
 `FreeModuleElement_generic_dense` rather than an instance of
 `Vector_symbolic_dense`.

 See the discussion at https://groups.google.com/group/sage-
 devel/browse_thread/thread/b20559a111041c3b

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11549>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
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