unassume -- delete the
properties of an identifier
Introductionunassume(x) deletes the properties of the
identifier x.
Call(s)unassume(x)
unassume( <Global>)
Parametersx |
- | an identifier or a list or a set of identifiers |
OptionsGlobal |
- | deletes the ``global property'' |
Returnsthe void object null().
Related
Functions
Detailsunassume serves for deleting properties of identifiers set via
assume. See ?property for a short
description of the property mechanism.x is a list or a set of identifiers, then the
properties of all specified identifiers are deleted.unassume() and
unassume(Global) are
equivalent. This deletes the ``global property'' which is used for all
identifiers. See assume
for details on setting a global property.delete x deletes
the value and the properties of the identifier x.
Example
1Properties are attached to the identifiers
x and y:
>> assume(x > 0): assume(y < 0): getprop(x), getprop(y)
> 0, < 0
>> sign(x), sign(y)
1, -1
unassume or delete deletes the properties:
>> unassume(x): delete y: getprop(x), getprop(y)
x, y
>> sign(x), sign(y)
sign(x), sign(y)
The properties of several identifiers can be deleted
simultaneously by passing a list or a set to unassume:
>> assume(x > y): unassume([x, y]): getprop(x), getprop(y)
x, y
Example
2All identifiers are assumed to represent real numbers. We set the corresponding global property:
>> assume(Global, Type::Real): getprop(x), getprop(y), getprop(z)
Type::Real, Type::Real, Type::Real
>> Re(x), Im(y), Re(x*y*z)
x, 0, x y z
unassume() or
unassume(Global) deletes the global
property:
>> unassume(): Re(x), Im(y), Re(x*y*z)
Re(x), Im(y), Re(x y z)