Changes between Version 38 and Version 43 of Ticket #24456


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Timestamp:
01/10/18 10:21:46 (4 years ago)
Author:
jdemeyer
Comment:

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  • Ticket #24456 – Description

    v38 v43  
    22
    33See also task ticket #17713.
     4
     5Use cases for this new "real field" object:
     6
     71. As some placeholder object to denote the field of real numbers, for example as output of `QQ.completion(oo)`. This implies that it should be a unique object.
     8
     92. As a Sage analogy to [https://www.python.org/dev/peps/pep-3141/ PEP 3141]: it should provide a way to ask "is `x` a real number" or "is `X` a substructure of the reals" or maybe "does parent `X` represent the real numbers". Also, we should be able to ask "is `x` an ''exact'' or ''approximate'' real number". Note that Sage already has partial support for PEP 3141 but only for elements (not parents).
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     113. As a pointers to all real field implementations (exact subrings and non-exact approximations). In particular it [what ???] should contain a class factory for all concrete real fields (e.g. the `create_RealField` function that is currently used for non-exact approximations).