Yes to me the consideration of mathematical symbolism helps make the issues involved in debating nominalism and reductionism clear.
Two things plus two things equals four things, because we define it that way. But what is a "thing"? In the end the usefulness of such symbolic equations becomes a matter of identifying what "thing" means. You can reduce everything over and over into a series of definitions as you try to assign meaning to your symbols, but in the end you have to remember that definition games can be circular and be a fool's errand, and the only way to prevent that is to tie things ultimately to observations of the facts observed by senses, anticipations, and feelings.
Surely there are practical "rules" or "conventions" about how to define things, based on experience, that will generally work to make the process more accurate. But in the end the definition game had better tie back to observations from the senses (or anticipations or feelings) or else the entire game collapses into circular abstractions.
It appears to me that Epicurus was waving major red flags about definition games, and he would have done the same with implying that all knowledge is a matter of definitions in the mind that are infinitely malleable. I would see the same issue with "rules of construction" such as we apply in the law, or as we deal with in deciding what is good logic vs what is a logical fallacy. Ultimately justice is not a matter of robotically following rules, nor is identifying truth a matter of definitions.
You have to eventually come to conclusions in order to survive, and it's fair to work as hard as you can to describe the best process of reasoning so that you can reproduce that process over and over.
But the cardinal and overriding rule seems likely to be that in the end rules cannot be considered to override the facts of the sensations ,anticipations, and feelings in ultimately analyzing any situation.
And the temptation to try to develop "rules" to be considered universal and infallible seems to be at least as great a hazard as the temptation to deny the usefulness of any and all rules. Epicurus certainly had his own rules of thought, such as PD23 and PD24, but they were always couched in terms of the ultimate rule being that the sensations, anticipations, and feelings are the ultimate abiter. In any situation of conflict between pure rules vs pure evidence (from the sensations, anticipations, and feelings, not including "rules of symbolic logic,") the ultimate arbiter of what we should acknowledge to be true is not the result of rules, but the result of facts established by the sensations, anticipations, and feelings.