Wiktionary
n. (context mathematics English) A function whose range is a subset of the set of complex numbers.
Usage examples of "complex function".
She knew that the best among them, those of the longest range and most complex function, had long since gone—.
But what if, as in many relationships of physics, this turns out to be an approximation to a more complex function whose deviation becomes more significant as distance increases?
Her speed would continue to rise slowly for weeks until she reached her limiting velocity, a complex function of hull shape and length.
The use of the term foreshadows another, more complex function of the hymn later in the play.
So Paul puts up this tremendous damn integral he had obtained by starting out with a complex function that he knew the answer to, taking out the real part of it and leaving only the complex part.
When we drop abstractions and take what we call our will in the act, we see that it is a very complex function.