AUTHORS:
Bases: sage.structure.unique_representation.UniqueRepresentation, sage.structure.parent.Parent
A class implementing a raw data structure for cartesian products of sets (and elements thereof). See cartesian_product for how to construct full fledge cartesian products.
Bases: sage.structure.element_wrapper.ElementWrapper
EXAMPLES:
sage: from sage.structure.element_wrapper import DummyParent
sage: a = ElementWrapper(DummyParent("A parent"), 1)
TESTS:
sage: TestSuite(a).run(skip = "_test_category")
sage: a = ElementWrapper(1, DummyParent("A parent"))
doctest:...: DeprecationWarning: the first argument must be a parent
See http://trac.sagemath.org/14519 for details.
Note
ElementWrapper is not intended to be used directly, hence the failing category test.
Returns the projection of self on the -th
summand of the cartesian product, as per
Sets.CartesianProducts.ElementMethods.summand_projection().
INPUTS:
- i – the index of a summand of the cartesian product
EXAMPLES:
sage: C = Sets().CartesianProducts().example(); C
The cartesian product of (Set of prime numbers (basic implementation), An example of an infinite enumerated set: the non negative integers, An example of a finite enumerated set: {1,2,3})
sage: x = C.an_element(); x
(47, 42, 1)
sage: x.summand_projection(1)
42
alias of ElementWrapper
EXAMPLES:
sage: C = Sets().CartesianProducts().example(); C
The cartesian product of (Set of prime numbers (basic implementation), An example of an infinite enumerated set: the non negative integers, An example of a finite enumerated set: {1,2,3})
sage: C.an_element()
(47, 42, 1)
Returns the natural projection onto the -th summand of self
as per
Sets.CartesianProducts.ParentMethods.summand_projection().
INPUTS:
- i – the index of a summand of self
EXAMPLES:
sage: C = Sets().CartesianProducts().example(); C
The cartesian product of (Set of prime numbers (basic implementation), An example of an infinite enumerated set: the non negative integers, An example of a finite enumerated set: {1,2,3})
sage: x = C.an_element(); x
(47, 42, 1)
sage: pi = C.summand_projection(1)
sage: pi(x)
42