passagemath-objects

10.8.4 verified Fri May 01 auth: no python

Core library for mathematical object infrastructure in the passagemath ecosystem. Provides base classes for Sage-like elements, parents, categories, coercion framework, and metaclasses. Part of the passagemath distribution (successor to SageMath components). Current version 10.8.4, supports Python 3.11-3.14. Released as part of passagemath v10.8.x series.

pip install passagemath-objects

Common errors

error ModuleNotFoundError: No module named 'sage' ↓

cause Code imports from old SageMath namespace (sage.structure) which is not present in passagemath.

fix

Change imports to passagemath.objects.*, e.g., 'from passagemath.objects.parent import Parent'

error ImportError: cannot import name 'CategoryInfinite' from 'passagemath.objects.category' ↓

cause CategoryInfinite was removed or renamed in recent versions.

fix

Use 'Category(is_finite=False)' instead of CategoryInfinite.

error ValueError: coercion model has not been initialized ↓

cause Attempting to use coercion without setting up the global coercion model.

fix

Ensure you create a Parent instance first (which initializes coercion) or call CoercionModel()._init_coercion().

Warnings

breaking All import paths changed from sage.* to passagemath.*. Code written for SageMath will not work. ↓

fix Replace sage structure imports with passagemath.objects.*

deprecated The class `CategoryInfinite` is deprecated; use `Category` with appropriate finiteness parameter. ↓

fix Replace `CategoryInfinite()` with `Category(is_finite=False)`

gotcha Coercion model initialization requires explicit setup; default model raises ValueError if used directly without configuration. ↓

fix Call `CoercionModel()._init_coercion()` after creation or use `from passagemath.objects.parent import Parent` which sets it up automatically.

gotcha Memory leaks may occur if elements are not properly garbage collected due to reference cycles in coercion caches. ↓

fix Use `gc.collect()` after cycles or call `Element._reset_cache()` periodically.

Install

pip install passagemath[objects]

Imports

Parent
wrong
```
from sage.structure.parent import Parent
```
correct
```
from passagemath.objects.parent import Parent
```
The import path changed from sage.* to passagemath.*; using sage.* triggers ModuleNotFoundError

Element

wrong

from sage.structure.element import Element

correct

from passagemath.objects.element import Element

Same namespace migration as Parent

Category

wrong

from sage.categories.category import Category

correct

from passagemath.objects.category import Category

Categories are now under passagemath.objects

CoercionModel
```
from passagemath.objects.coerce import CoercionModel
```
No common wrong import; previously in sage.structure.coerce

Quickstart

Create a custom parent class with category support using passagemath-objects.

from passagemath.objects.parent import Parent
from passagemath.objects.element import Element
from passagemath.objects.category import Category

class MyParent(Parent):
    def __init__(self):
        super().__init__(category=Category())

p = MyParent()
print(isinstance(p, Parent))  # True