Dear David,
> Natural numbers are missing, but it is not clear that one
> implementation
> will suit all intended uses:
>
> 1) as a poset with i <= i+j (extended by other cardinalities);
> 2) as a poset with i <= i*j;
> 3) as an additive abelian monoid;
> 4) as a multiplicative abelian monoid;
> 5) etc.
>
> Until one considers N in the context of its possible structures and
> morphisms,
> one might as well restricting to the subset of integers.
Sure ! That means that there is several different object which we call
roughly "the set of natural number". My intend is to give the most basic
functionality (ie: __contains__ cardinality and __iter__).
Please vote for your favorite names:
- NaturalNumbers
- Naturals
- NaturalIntegers
- NonNegativeIntegers
/
- PositiveNaturals
- PositiveIntegers
...
Concerning poset, it is a (more or less long term) project to have an
infrastructure for generic posets including those two. The vague plan is to
change the order structure by picking a different parent/class.
for 3) and 4) It should be very easy for the user to write/pick the one he
needs.
Cheers,
Florent
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