How about ANY FINITE SEQUENCE AT ALL?

  • tetris11
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    21 hours ago

    Isnt this a stupid example though, because obviously if you remove all penguins from the zoo, you’re not going to see any penguins

    • Lanthanae@lemmy.blahaj.zone
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      18 hours ago

      Its not stupid. To disprove a claim that states “All X have Y” then you only need ONE example. So, as pick a really obvious example.

      • Umbrias@beehaw.org
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        12 hours ago

        it’s not a good example because you’ve only changed the symbolic representation and not the numerical value. the op’s question is identical when you convert to binary. thir is not a counterexample and does not prove anything.

            • spireghost@lemmy.zip
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              2 hours ago

              The question is

              Since pi is infinite and non-repeating, would it mean…

              Then the answer is mathematically, no. If X is infinite and non-repeating it doesn’t.

              If a number is normal, infinite, and non-repeating, then yes.

              To answer the real question “Does any finite sequence of non-repeating numbers appear somewhere in Pi?”

              The answer depends on if Pi is normal or not, but not necessarily

        • orcrist@lemm.ee
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          7 hours ago

          Please read it all again. They didn’t rely on the conversion. It’s just a convenient way to create a counterexample.

          Anyway, here’s a simple equivalent. Let’s consider a number like pi except that wherever pi has a 9, this new number has a 1. This new number is infinite and doesn’t repeat. So it also answers the original question.

          • Umbrias@beehaw.org
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            4 hours ago

            “please consider a number that isnt pi” so not relevant, gotcha. it does not answer the original question, this new number is not normal, sure, but that has no bearing on if pi is normal.

            • spireghost@lemmy.zip
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              2 hours ago

              OK, fine. Imagine that in pi after the quadrillionth digit, all 1s are replaced with 9. It still holds

        • Lanthanae@lemmy.blahaj.zone
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          17 hours ago

          In terms of formal logic, this…

          Since Pi is infinite and non-repeating, would that mean any finite sequence of non-repeating digits from 0-9 should appear somewhere in Pi in base 10?

          …and this…

          Does any possible string of infinite non-repeating digits contain every possible finite sequence of non repeating digits?

          are equivalent statements.

          The phrase “since X, would that mean Y” is the same as asking “is X a sufficient condition for Y”. Providing ANY example of X WITHOUT Y is a counter-example which proves X is NOT a sufficient condition.

          The 1.010010001… example is literally one that is taught in classes to disprove OPs exact hypothesis. This isn’t a discussion where we’re both offering different perspectives and working towards a truth we don’t both see, thus is a discussion where you’re factually wrong and I’m trying to help you learn why lol.

          • Sheldan@lemmy.world
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            13 hours ago

            Is the 1.0010101 just another sequence with similar properties? And this sequence with similar properties just behaves differently than pi.

            Others mentioned a zoo and a penguin. If you say that a zoo will contain a penguin, and then take one that doesn’t, then obviously it will not contain a penguin. If you take a sequence that only consists of 0 and 1 and it doesn’t contain a 2, then it obviously won’t.

            But I find the example confusing to take pi, transform it and then say “yeah, this transformed pi doesn’t have it anymore, so obviously pi doesn’t” If I take all the 2s out of pi, then it will obviously not contain any 2 anymore, but it will also not be really be pi anymore, but just another sequence of infinite length and non repeating.

            So, while it is true that the two properties do not necessarily lead to this behavior. The example of transforming pi to something is more confusing than helping.

            • orcrist@lemm.ee
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              12 hours ago

              The original question was not exactly about pi in base ten. It was about infinite non-repeating numbers. The comment answered the question by providing a counterexample to the proffered claim. It was perfectly good math.

              You have switched focus to a different question. And that is fine, but please recognize that you have done so. See other comment threads for more information about pi itself.

              • Sheldan@lemmy.world
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                4 hours ago

                I see that the context is a different one and i also understand formal logic (contrary to what the other comment on my post says)

                It’s just that if the topic is pi, I find it potentially confusing (and not necessary) to construct a different example which is based on pi (pi in binary and interpreted as base 10) in order to show something, because one might associate this with the original statement.

                While this is faulty logic to do so, why not just use an example which doesn’t use pi at all in order to eliminate any potential.

                I did realize now that part of my post could be Interpreted in a way, that I did follow this faulty logic -> I didn’t

        • stevedice@sh.itjust.works
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          15 hours ago

          Since Pi is infinite and non-repeating, would that mean any finite sequence of non-repeating digits from 0-9 should appear somewhere in Pi in base 10?

          Does any possible string of infinite non-repeating digits contain every possible finite sequence of non repeating digits?

          Let’s abstract this.

          S = an arbitrary string of numbers

          X = is infinite

          Y = is non-repeating

          Z = contains every possible sequence of finite digits

          Now your statements become:

          Since S is X and Y, does that mean that it’s also Z?

          Does any S that is X and Y, also Z?"

    • untorquer@lemmy.world
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      20 hours ago

      The explanation is misdirecting because yes they’re removing the penguins from the zoo. But they also interpreted the question as to if the zoo had infinite non-repeating exhibits whether it would NECESSARILY contain penguins. So all they had to show was that the penguins weren’t necessary.

      By tying the example to pi they seemed to be trying to show something about pi. I don’t think that was the intention.

      • juliebean@lemm.ee
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        13 hours ago

        i just figured using pi was an easy way to acquire a known irrational number, not trying to make any special point about it.