How about ANY FINITE SEQUENCE AT ALL?

  • tetris11@lemmy.ml
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    14 days 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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      14 days 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.

        • Lanthanae@lemmy.blahaj.zone
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          14 days 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.

        • stevedice@sh.itjust.works
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          14 days 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?"

      • Umbrias@beehaw.org
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        13 days 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.

        • orcrist@lemm.ee
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          13 days 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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            13 days 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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              13 days 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