this post was submitted on 26 Dec 2024
236 points (98.8% liked)
Asklemmy
49195 readers
541 users here now
A loosely moderated place to ask open-ended questions
Search asklemmy π
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- !lemmy411@lemmy.ca: a community for finding communities
~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~
founded 6 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
no. it merely being infinitely non-repeating is insufficient to say that it contains any particular finite string.
for instance, write out pi in base 2, and reinterpret as base 10.
it is infinitely non-repeating, but nowhere will you find a 2.
i've often heard it said that pi, in particular, does contain any finite sequence of digits, but i haven't seen a proof of that myself, and if it did exist, it would have to depend on more than its irrationality.
Isnt this a stupid example though, because obviously if you remove all penguins from the zoo, you're not going to see any penguins
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.
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.
"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.
OK, fine. Imagine that in pi after the quadrillionth digit, all 1s are replaced with 9. It still holds
"ok fine consider a number that still isn't pi, it still holds." ??
Prove that said number isn't pi.
isnt, qed
Hmm, ok. Let me retry.
The digits of pi are not proven to be uniform or randomly distributed according to any pattern.
Pi could have a point where it stops having 9's at all.
If that's the case, it would not contain all sequences that contain the digit 9, and could not contain all sequences.
While we can't look at all the digits of Pi, we could consider that the uniform behavior of the digits in pi ends at some point, and wherever there would usually be a 9, the digit is instead a 1. This new number candidate for pi is infinite, doesnβt repeat and contains all the known properties of pi.
Therefore, it is possible that not any finite sequence of non-repeating numbers would appear somewhere in Pi.
i am aware nobody has proven pi is normal.
They didn't convert anything to anything, and the 1.010010001... number isn't binary
then it's not relevant to the question as it is not pi.
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
In terms of formal logic, this...
...and this...
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.
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.
We need to start teaching formal logic in grade schools I'm going insane.
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
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: