So is the issue that the max function knows how to handle and parse the explicit numeric inputs of 5 6 etc, whereas Maximum is expecting to pull it out of a named dimensioned array? The error is weird for sure, but I gotta say that is pretty cool to have the two similar functions to do those two different tasks. I might be reading that wrong as I'm sure you remember my coding is limited to a specific language that looks very different. So I apologize if my interpretation and question is beyond stupid.
Naw, that wasn't my point. The maximum function actually uses max in it's implementation. It makes sense - max operates on two arguments (one, actually, but that's going deep down the Haskell rabbit hole) while maximum works on lists. What I found crazy was how cryptic the error message was. If you had enough knowledge of the language to understand it, you probably wouldn't have made the error in the first place.