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unassume -- delete the properties of an identifier

Introduction

unassume(x) deletes the properties of the identifier x.

Call(s)

unassume(x)
unassume( <Global>)

Parameters

x - an identifier or a list or a set of identifiers

Options

Global - deletes the ``global property''

Returns

the void object null().

Related Functions

assume, delete, getprop, is

Details

Example 1

Properties 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 2

All 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)

Changes




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