• Miller@lemmy.world
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        1 day ago

        My old statistics lecturer would write x-¹ as shorthand meaning everything that is not x, I thought it was in more common usage but perhaps not. I know it more generally means the reciprocal, he just expected you to know which he meant by context.

        • nyan@lemmy.cafe
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          1 day ago

          x-¹

          Where I come from, that’s read as “x to the [power of] minus one”. “x minus one” is, well, x - 1. Not the same thing at all.

          (I admit, my chances of deciphering what you meant might not have been all that high even if you’d used the correct phrasing, but without it, the chance was zero.)

          • Miller@lemmy.world
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            15 hours ago

            It was a shorthand he used, he wrote it as a superscript, it must of been his own, it was useful in terms of statistics analysis.

            • SCmSTR@lemmy.blahaj.zone
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              1 day ago

              It has been a LONG time since I did any real math and never took statistics, but wouldn’t x^(-1) just be 1/(x)? I don’t know if that equates to “everything that isn’t x”. I feel like there’s a specific way to write that, but a negative exponent is not that, I don’t think, but also I have no idea.

              I looked it up. Looks like this stuff is maybe from set theory? Which I sooorrrrt of remember doing at some point?

              My best guess is your professor either said something from this, or you misremembered, or I’m totally off base and I’m still curious.

              https://en.wikipedia.org/wiki/Complement_(set_theory)

              • Miller@lemmy.world
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                1 day ago

                Your best guess is reasonable, I may have misremembered, it could have been A’ spoken as A dash and meaning the complement and I hallucinated the negative but I think I recall some noted confusion with the reciprocal x-¹ = 1/x.

            • nyan@lemmy.cafe
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              1 day ago

              We may also be separated by a common llanguage—“lecturer” isn’t a word that’s much used in Canada. I’ve only encountered it as a Briticism.

              • Miller@lemmy.world
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                1 day ago

                I read your reply as snarky but I think it may have been just differences in phrasing.