Dear all,

vdelecroix schrieb am Freitag, 16. Oktober 2020 um 07:50:46 UTC+2:

> I agree that these are not fields in the mathematical sense. And Sage 
> knows about it 
>
> sage: RR.is_exact() 
>
>
> False 
> sage: QQ.is_exact() 
>
>
> True 
>

That's actually what I meant. We also have:

sage: RR in Fields()
True

We could say that RR is a non-exact realization of an exact mathematical 
object which is a field, so that both outputs make somehow sense. But if we 
want it as rigorously as requested, we must as well require

sage: RR in Fields()
False

If that is what we want, we perhaps need another category, e.g. 
"PseudoFields" in order to maintain most algorithms, e.g. for matrices.

I'd suggest a workaround: so what about "Real Field realized by 
Floating-point arithmetics of precision xx" and keep the above behavior? 
And then similarly for interval arithmetics and ball arithmetics.

Best,
Michael


> However, they are much more than sets as they come with approximations 
> of the field operations (+, x, ^-1). Maybe a reasonable terminology 
> would be "numerical field"? And in this regard, RealFloatingPointField 
> perfectly make sense. I am against RealFloats. 
>
> Le 15/10/2020 à 11:24, Samuel Lelievre a écrit : 
> > 2020-10-15 08:21:06 UTC, John Cremona: 
> >> 
> >> I was expecting someone more pedantic than me to point out that this 
> set 
> >> is not a field in the mathematical sense. Since this is a big change 
> > anyway 
> >> (at least to a lot of doctest outputs) should we think more carefully 
> > about 
> >> what we want to call RR? Instead of "Real floating-point field with x 
> bits 
> >> of precision" we could have "Real floating-point numbers with x bits of 
> >> precision" perhaps. (With an implied "The set of" in front). 
> > 
> > Good point! 
> > 
> > I like "Real floating-point numbers with x bits of precision" 
> > with short name RFN for real floating-point numbers. 
> > 
> > Or shorter: "RealFloats" -> "Real floats with x bits of precision", 
> > short name RF for the standard one with 53 bits of precision. 
> > 
> > Consistency would dictate to rename and change the string representation 
> > for all of the following: 
> > 
> > - ComplexField -> ComplexFloats 
> > - RealField -> RealFloats 
> > 
> > - ComplexDoubleField -> ComplexDoubleFloats 
> > - RealDoubleField -> RealDoubleFloats 
> > 
> > - ComplexBallField -> ComplexFloatBalls 
> > - ComplexBallField -> RealFloatBalls 
> > 
> > - ComplexIntervalField -> ComplexFloatIntervals 
> > - RealIntervalField -> RealFloatIntervals 
> > 
> > and maybe more sort-of-fields that can be listed using: 
> > ``` 
> > sage: [g for g in globals() if 'ield' in g] 
> > ``` 
> > 
> > - ComplexLazyField -> ComplexLazyFloats? 
> > - RealLazyField -> RealLazyFloats? 
> > 
> > - MPComplexField -> MPComplexFloats? 
> > 
> > What about pAdicField? 
> > 
> > Of course we can do things one at a time, but it's good to plan ahead 
> > and maybe have a meta-ticket to keep track of what is done and what 
> > needs to be done. 
> > 
> > Side remark: should ComplexIntervalFieldElement, FieldElement 
> > and NumberFieldElement be removed from the global namespace? 
> > 
>

-- 
You received this message because you are subscribed to the Google Groups 
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sage-devel+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/sage-devel/5617ca3b-bc86-40e7-b313-af0cccf7f97bn%40googlegroups.com.

Reply via email to