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Complex infinity

This functionality does not run in MATLAB.

`complexInfinity`

`complexInfinity` represents the only non-complex
point of the one-point compactification of the complex numbers.

Mathematically, `complexInfinity` is the north
pole of the Riemann sphere, with the unit circle as equator and the
point 0 at the south pole.

With respect to arithmetic, `complexInfinity` behaves
like "`1/0`". In particular, non-zero
complex numbers may be multiplied or divided by `complexInfinity` or `1/
complexInfinity`. Adding `complexInfinity` to
a finite number yields again `complexInfinity`.

With respect to arithmetical operations, `complexInfinity` is
incompatible with the real `infinity`.

`complexInfinity` can be used in arithmetical
operations with complex numbers. The result in multiplications or
divisions is either `complexInfinity`, `0`,
or `undefined`:

3*complexInfinity, I*complexInfinity, 0*complexInfinity; 3/complexInfinity, I/complexInfinity, 0/complexInfinity; complexInfinity/3, complexInfinity/I; complexInfinity*complexInfinity, complexInfinity/complexInfinity;

The result in additions is `undefined` if one of the operands is infinite,
and `complexInfinity` otherwise:

complexInfinity + complexInfinity, infinity + complexInfinity; 3 + complexInfinity, I + complexInfinity, PI + complexInfinity

Symbolic expressions in arithmetical operations involving `complexInfinity` are
implicitly assumed to be different from both `0` and `complexInfinity`:

delete x: x*complexInfinity, x/complexInfinity, complexInfinity/x, x + complexInfinity

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