the thing is, a little working knowledge of set theory lets you do really interesting things with sociological ideas, as long as you do one little thing first. to handle edge cases, since people aren't as clear-cut as elements in a set, we need a new rule. in mathematics, a rule is called an axiom, so we go:
The Axiom of Exceptions: given the set X of all people, any two subsets of X called n and m and defined by a single trait implying opposition to each other such that {a∈n|a∉m} ∧ {a∈m|a∉n} is true for any person a where a∈X, there exists a theoretical person b, given b∈X, for whom either b∈n∩m or b∉n∪m is true but not both. this person b should only be considered contradictory to n and m if their existence or nonexistence is fundamental to the proof.
sloppy notation aside (i haven't had to write sets in a couple years) what this means is if you have any two categories that should be mutually exclusive opposites, there can be a person who is either both or neither thing, but you can ignore them as long as they don't actively disprove the point you're making.
tl:dr, "if you have an edge case that would complicate the point, you can leave it out unless doing so changes the answer you get"
this accounts for things like "nonbinary people are inherently not cisgender because no one is assigned nonbinary at birth" having edge cases like multigender people who still consider themselves partly cis by going "well if they aren't arguably actively important to the point we don't need to consider them"
and once you've done that, it's off to the races. you can represent all kinds of stuff this way. this is also a fantastic way to stress-test feminist and queer theorist ideas by running them through a mathematical proof and looking for a case in which the given statement isn't true. if you can find one, the Axiom of Exceptions says that if you can use it to disprove or prove the statement you may do so, so you can. (this is a favorite technique of mine for things that sound good but are nuanced enough to not really be accurate)
