this post was submitted on 26 Dec 2024
218 points (98.2% liked)
Asklemmy
44171 readers
1825 users here now
A loosely moderated place to ask open-ended questions
Search asklemmy ๐
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 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
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.
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
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.
"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
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.
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.
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:
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.
i just figured using pi was an easy way to acquire a known irrational number, not trying to make any special point about it.