This is not what I see on the current beta:
sage: R.<x> = LaurentSeriesRing(QQ)
sage: R.zero().degree()
-1
sage: R.<x> = LazyLaurentSeriesRing(QQ)
sage: R.zero().degree()
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
Cell In[4], line 1
----> 1 R.zero().degree()
File ~/sage/sage/src/sage/structure/element.pyx:489, in
sage.structure.element.Element.__getattr__()
487 AttributeError:
'LeftZeroSemigroup_with_category.element_class' object has no attribute
'blah_blah'...
488 """
--> 489 return self.getattr_from_category(name)
490
491 cdef getattr_from_category(self, name) noexcept:
File ~/sage/sage/src/sage/structure/element.pyx:502, in
sage.structure.element.Element.getattr_from_category()
500 else:
501 cls = P._abstract_element_class
--> 502 return getattr_from_other_class(self, cls, name)
503
504 def __dir__(self):
File ~/sage/sage/src/sage/cpython/getattr.pyx:357, in
sage.cpython.getattr.getattr_from_other_class()
355 dummy_error_message.cls = type(self)
356 dummy_error_message.name = name
--> 357 raise AttributeError(dummy_error_message)
358 cdef PyObject* attr = instance_getattr(cls, name)
359 if attr is NULL:
AttributeError: 'LazyLaurentSeriesRing_with_category.element_class' object
has no attribute 'degree'
On Wednesday, February 28, 2024 at 12:05:32 PM UTC Martin R wrote:
> LazyLaurentSeriesRing(QQ) currently gives +Infinity.
>
> On Wednesday 28 February 2024 at 12:50:45 UTC+1 Giacomo Pope wrote:
>
>> While chasing various bugs which appeared in the CI, I ended up adding a
>> small method for computing random elements for the LaurentPolynomialRing
>> class.
>>
>> When writing randomised testing I got myself confused about the degree of
>> the zero polynomial. For the univariate and multivariate polynomial rings,
>> we currently use that the degree for 0 (both R(0).degree() as well as
>> R(0).degree(x)) is -1. This is unambiguous for the case of these types.
>>
>> However for the LaurentPolynomialRings, a polynomial with negative
>> valuation is very natural. For example the following code snippet shows the
>> ambiguity.
>>
>> sage: L.<x> = LaurentPolynomialRing(QQ)
>> sage: f = (1/x); f
>> x^-1
>> sage: f.degree()
>> -1
>> sage: L.zero().degree()
>> -1
>>
>> I don't feel familiar enough with the mathematics here and the usual use
>> cases in sage to offer a PR "fixing" this, or whether it even needs fixing.
>> However, I got confused so I thought maybe others might get confused and
>> someone on this list might have a suggestion.
>>
>> I think the "usual" suggestion would be to have the degree as -infty, but
>> then there's a question about whether this should be done for other
>> polynomial rings...
>>
>> I made an issue for this on GitHub too:
>>
>> https://github.com/sagemath/sage/issues/37491
>>
>
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