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use Parent in infinity #37564

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Merged
vbraun merged 1 commit into from
Mar 31, 2024
Merged

use Parent in infinity #37564

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27 changes: 9 additions & 18 deletions src/sage/rings/infinity.py
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Original file line number Diff line number Diff line change
Expand Up @@ -219,7 +219,9 @@

import sage.rings.abc

from sage.structure.parent import Parent
from sage.categories.rings import Rings
from sage.categories.semirings import Semirings
from sage.misc.fast_methods import Singleton
from sage.misc.lazy_import import lazy_import
from sage.rings.ring import CommutativeRing
Expand All @@ -232,7 +234,7 @@
_obj = {}


class _uniq():
class _uniq:
def __new__(cls, *args):
"""
This ensures uniqueness of these objects.
Expand All @@ -248,7 +250,7 @@ def __new__(cls, *args):
return O


class AnInfinity():
class AnInfinity:
"""
TESTS::

Expand Down Expand Up @@ -560,7 +562,7 @@ def _sage_input_(self, sib, coerced):
return -sib.name('oo')


class UnsignedInfinityRing_class(Singleton, CommutativeRing):
class UnsignedInfinityRing_class(Singleton, Parent):

def __init__(self):
"""
Expand All @@ -584,7 +586,9 @@ def __init__(self):
sage: UnsignedInfinityRing(3) == UnsignedInfinityRing(-19.5)
True
"""
CommutativeRing.__init__(self, self, names=('oo',), normalize=False)
cat = Semirings().Commutative()
Parent.__init__(self, self, names=('oo',), normalize=False,
category=cat)

def ngens(self) -> int:
"""
Expand All @@ -599,19 +603,6 @@ def ngens(self) -> int:
"""
return 1

def fraction_field(self):
"""
The unsigned infinity ring isn't an integral domain.

EXAMPLES::

sage: UnsignedInfinityRing.fraction_field()
Traceback (most recent call last):
...
TypeError: infinity 'ring' has no fraction field
"""
raise TypeError("infinity 'ring' has no fraction field")

def gen(self, n=0):
"""
The "generator" of ``self`` is the infinity object.
Expand Down Expand Up @@ -1869,7 +1860,7 @@ def test_signed_infinity(pos_inf):
sage: test_signed_infinity(RIF(oo)) # needs sage.rings.real_interval_field
sage: test_signed_infinity(SR(oo)) # needs sage.symbolic
"""
msg = 'testing {} ({})'.format(pos_inf, type(pos_inf))
msg = f'testing {pos_inf} ({type(pos_inf)})'
assert InfinityRing(pos_inf) is infinity, msg
assert InfinityRing(-pos_inf) is minus_infinity, msg
assert infinity == pos_inf, msg
Expand Down