Poor Man’s map#
- class sage.categories.poor_man_map.PoorManMap(function, domain=None, codomain=None, name=None)#
Bases:
SageObject
A class for maps between sets which are not (yet) modeled by parents
Could possibly disappear when all combinatorial classes / enumerated sets will be parents
INPUT:
function
– a callable or an iterable of callables. This represents the underlying function used to implement this map. If it is an iterable, then the callables will be composed to implement this map.domain
– the domain of this map orNone
if the domain is not known or should remain unspecifiedcodomain
– the codomain of this map orNone
if the codomain is not known or should remain unspecifiedname
– a name for this map orNone
if this map has no particular name
EXAMPLES:
sage: from sage.categories.poor_man_map import PoorManMap sage: f = PoorManMap(factorial, domain = (1, 2, 3), codomain = (1, 2, 6)) sage: f A map from (1, 2, 3) to (1, 2, 6) sage: f(3) 6
The composition of several functions can be created by passing in a tuple of functions:
sage: i = PoorManMap((factorial, sqrt), domain= (1, 4, 9), codomain = (1, 2, 6))
However, the same effect can also be achieved by just composing maps:
sage: g = PoorManMap(factorial, domain = (1, 2, 3), codomain = (1, 2, 6)) sage: h = PoorManMap(sqrt, domain = (1, 4, 9), codomain = (1, 2, 3)) sage: i == g*h True
- codomain()#
Returns the codomain of
self
EXAMPLES:
sage: from sage.categories.poor_man_map import PoorManMap sage: PoorManMap(lambda x: x+1, domain = (1,2,3), codomain = (2,3,4)).codomain() (2, 3, 4)
- domain()#
Returns the domain of
self
EXAMPLES:
sage: from sage.categories.poor_man_map import PoorManMap sage: PoorManMap(lambda x: x+1, domain = (1,2,3), codomain = (2,3,4)).domain() (1, 2, 3)