#8335: Finite Field lattices for (pseudo-)Conway polynomials
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       Reporter:  roed                          |         Owner:  AlexGhitza    
                
           Type:  enhancement                   |        Status:  needs_review  
                
       Priority:  major                         |     Milestone:  sage-5.11     
                
      Component:  algebra                       |    Resolution:                
                
       Keywords:  days49                        |   Work issues:                
                
Report Upstream:  N/A                           |     Reviewers:  Jean-Pierre 
Flori, Luca De Feo
        Authors:  David Roe, Jean-Pierre Flori  |     Merged in:                
                
   Dependencies:  #13894                        |      Stopgaps:                
                
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Comment (by jpflori):

 Replying to [comment:71 pbruin]:
 > In relation to #12142, I am currently working on a patch that makes the
 construction of irreducible polynomials independent of the finite field
 implementations (prime_modn, givaro, ntl_gf2e, ext_pari and the future
 pari_ffelt).  Currently every finite field implementation has to do its
 own parsing of string values of modulus (like 'conway', 'random' etc.).
 It would be more elegant to handle all these string values in the generic
 constructor, and always pass an actual polynomial to the finite field
 implementation.
 >
 > In the current version of Sage, the only situation in which the
 implementation needs to know whether the field is defined by a Conway
 polynomial is when converting elements to GAP.  This means that always
 passing a polynomial as the modulus is fine, as long as one can check if
 the polynomial is a Conway polynomial if and when it is needed.  This is
 easy to do by checking the database.
 Beware that the last patch which contains my modification to the two
 original patches by David changes quite a lot of thing.
 In particular, I think that with it modulus contains the real modulus as
 well and I use additional attributes to check for pseudo-Conway
 construction.

 Also note that the real nice addition of this patch is mainly the
 compatible embeddings.
 Indeed, for practical purposes, it seems that only the Conway polynomials
 from the databse will be used.
 Constructing pseudo-Conway polynomials is quite as  slow as contructions
 genuine Conway polynomials so when you will actually use them, i.e. for
 quite large parameters because you have to be outside of the Conway
 database, it will already be quite slow and unpractical.

 >
 > With your patch, each implementation gets an increased dependence on
 string values for the modulus parameter.  I am wondering if this can be
 avoided by doing all the pseudo-Conway related stuff inside the generic
 finite field code.
 >
 > [...to be continued...]

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8335#comment:72>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
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