Trivial question. Consider these "multiplicative" functions $y = f(x,w,z)$:
$$ y = xwz $$
$$ y = \frac{x^2}{wz} $$
where $x, w, z$ are all positive.
They key is that all terms are multiplicating each other, and there are no summation terms, nor logarithms or exponents. So examples which I do not want are:
$$ y = 2+xwz $$
$$ y = \frac{2+x^2}{wz} $$
$$ y = \ln(x)\frac{z+1}{e^w} $$
Thus, all I want is that the function is homogeneous and "subterms" are "multiplicative". Homogeneous but not "multiplicative" functions do not qualify (e.g. $y = x + w + z$).
The question is: what's the name for this type of functions (if any)? I thought it would be "multiplicative function" but that seems to be another type altogether, related to prime numbers which have nothing to do with my case.