a year and a half into my #math phd, i still forget that "open" and "closed" aren't opposites.
i hate this convention
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@stripey I kind of think of it as a set is open because there's always a little more wiggle room anywhere in it, always a little more space, so that's open, whereas a closet set has all of its boundary, so it's like it's fenced-in, closed.
Also, they're not opposites, but they're complements, but you knew that already.
