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Type and property representing zero

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testtype(obj, Type::Zero)
assume(x, Type::Zero)
is(ex, Type::Zero)


testtype(obj, Type::Zero ) is equivalent to iszero(obj). Type::Zero is a property, too, which can be used in an assume call.

The call testtype(obj, Type::Zero) is equivalent to iszero(obj), which performs a syntactical test if obj is zero. If it is, the call returns TRUE, otherwise, FALSE is returned.

The call assume(x, Type::Zero) marks the identifier x as zero.

The call is(ex, Type::Zero) derives, whether the expression ex is zero (or this property can be derived).

This type represents a property that can be used in assume and is.

The call assume(x = 0) has the same meaning as assume(x, Type::Zero).


Example 1

testtype determines the syntactical equality to zero:

testtype(0.0, Type::Zero)

testtype(x, Type::Zero)

Example 2

Type::Zero can be used within assume and is:

is(x, Type::Zero)

Assumption that x is zero:

assume(x, Type::Zero):
is(x^2, Type::Zero)

The next example shows the difference between testtype and is:

is(x, Type::Zero), testtype(x, Type::Zero)

Now the property of x is removed:

delete x:
is(x, Type::Zero), testtype(x, Type::Zero)

A positive number cannot be zero:

assume(x > 0):
is(x, Type::Zero), testtype(x, Type::Zero)

But in the next example x could be zero:

assume(x >= 0):
is(x, Type::Zero), testtype(x, Type::Zero)

delete x:



Any MuPAD® object


An identifier or a mathematical expression containing identifiers


An arithmetical expression

Return Values

See testtype, assume and is

See Also

MuPAD Functions

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