Rubicund

The author does address this further on page 14 of SI and provides an alternative of:

−z = 1 − (e − ((e − 1) − z))

On page 11, the paper explicitly states:

EML-compiled formulas work flawlessly in symbolic Mathematica and IEEE754 floating-point… This is because some formulas internally might rely on the following properties of extended reals: ln 0 = −∞, e^(−∞) = 0.

And then follows with:

But EML expressions in general do not work ‘out of the box’ in pure Python/Julia or numerical Mathematica.

Thus, the paper’s completeness claim depends on a non-standard arithmetic convention (ln(0) = -∞), not just complex numbers as it primarily advertises. While the paper is transparent about this, it is however, buried on page 11 rather than foregrounded as a core caveat. Your comment deserves credit for flagging it.