As per a recent comment this thread is meant to voice contrarian opinions, that is anything this community tends not to agree with. Thus I ask you to post your contrarian views and upvote anything you do not agree with based on personal beliefs. Spam and trolling still needs to be downvoted.
That makes a lot of sense. I asked about explicit declaration versus implicit assumption because assumptions of this sort do exist in social models. They're just treated as unmodeled characteristics either of agents or of reality. We can make these assumptions because they either don't inform the phenomenon we're investigating (e.g. infinite ammunition can be implicitly assumed in an agent-based model of battlefield medic behavior because we're not interested in the draw-down or conclusion of the battle in the absence of a decisive victory) or the model's purpose is to investigate relationships within a plausible range (which sounds like your use case). That said, I'm very curious about the existence of models for which explicitly setting a boundary of infinity can reduce computational complexity. It seems like such a thing is either provably possible or (more likely) provably impossible. Know of anything like that?
I see your distinction now. That is a good classification.
To go back to the low-Mach/incompressible flow model, I have seen series expansions in terms of the Mach number applied to (subsets of) the fluid flow equations, and the low-Mach approximation is found by setting the Mach number to zero. (Ma = v / c, so if c, the speed of sound, approaches infinity, then Ma goes to 0.) So it seems that you can go the other direction to derive equations starting with the goal of modeling a low-Mach flow, but that's not typically what I see. There's no "Mach numb... (read more)