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00:02
@GratefulDisciple Many. Rent-A-Girlfriend being the most recent
 
2 hours later…
02:30
definitely edgy
02:51
Is there any sort of search engine or database in which you can enter an arbitrary Cayley Table and it will return all known phenomena that Cayley Table models?
(when I say arbitrary Cayley Table, I mean preferably the input doesn't have to satisfy all group axioms)
 
2 hours later…
05:21
6 stars for 'about 25'!
2
06:18
7 actually, your comment has 6 :P
 
3 hours later…
123
123
09:09
Hello Everyone
 
1 hour later…
10:25
Why is it necessarily true that in a circular planar region, which is just an open disk with finitely many open disks removed, that if a piecewise smooth curve joins points of the boundary of the region on different boundary components , but otherwise stays inside the region, and does not disconnect the region, that the connectivity of the region decreases exactly by one after cutting the region along the curve?
I can see this is true if the curve were a Jordan arc
but im not sure how to prove it for a general piecewise smooth cut
even in the case of a Jordan arc, I can only see why its true, but I cant furnish a formal proof (im guessing we could contract away the Jordan arc, and this would be sufficient to show the connectivity decreases by one)
Sorry, a circular region has finitely many closed disks removed (its open after all)
 
1 hour later…
11:42
Good morning, even if it is evening. I using chat room for first time. Please forgive if I do something wrong. Can I ask here about one problem of logic? Thank You.
$ \pi $ Latex?
S is False.
https://chat.openai.com/share/c9ba0560-73a7-4c8c-96b6-1ccfdee60476
11:59
Why not copy and paste the question in here @VitalieGhelbert?
How?
Just as simple copy and paste, just so?
Problem of Logic:

Argument A imply statement S is true, otherwise S is false.
Argument B is equivalent with A.
If we accept B, A become non-reason argument to imply S is true, therefore S is false.
If we reject B, we reject A that imply S is true, resulting S is false.

Is S true of false?
Why I am asking, because ChatGPT deduced a solution and I was wondering because the answer is what I expected.

S is False.
https://chat.openai.com/share/c9ba0560-73a7-4c8c-96b6-1ccfdee60476
12:17
what is a non reason argument, why does accepting B make S false? Why does rejecting B imply S is false? The entire premise makes no sense to me
seems like you just wrote If we accept B, ... , therefore S is false
then you wrote If we reject B , ... , S is false
so of course chat gpt is going to say S is false based on your premises
because you just wrote S is false
No, i asked the question "Is S true of false?", taking in account A, B relations with statement S.
yeah, but what do you mean by If we accept B ... S is false, If we reject B ... S is false
you wrote some stuff in the ... part, which makes no sense to me
honestly it seems like it doesnt matter what you wrote in the ... part
when you combine those two premises, you get S is false
if I was to translate what you wrote , it would be: A <-> S , A <-> B , B -> !S, !B -> !S
I just formulated relations between arguments A, B and statement S.
After he answered the question, I give him the values for A, B and S.
And He once again returned the answer I was expecting!
That is way I was so amazed! How can that be!
He resolved a Logica Problem.
lol
chatgpt is just very polite
:) Yes. It is impossible. Because all Internet says contrary to this solution we get!
One against infinitely many! :D War!
12:27
itll give you an answer to anything at all, including nonsensical questions
what would be interesting is if chatgpt could tell you that your premises are contradictory
maybe you should ask it
Yes. When I asked Him the question "is 0 odd or even?" I get the classical answer "0 is even", that we find everywhere on the internet. But when I give Him reformulated Problem of Logic, he concluded what I was expecting! Statement "0 is even" is false! One against infinitely many on the internet! War! :D
or rather, your premises arent contradictory, but they should result in A (and B) being false
okay, but when you start putting concrete things into your premises, you cant expect a valid conclusion
ugh, it doesnt matter
Maybe. But that is what resulted from first shot of question. ChatCPT follow just rationament of implications, therefore we get what we expected.
you were expecting 0 is even to be false based on?
I was expecting he will conclude "0 is even" to be false. And He did that. :)
12:36
okay, so what?
doesnt that show chatgpt is pretty unrefined?
That show that ChatGPT can be learn to answer as a parrot, but if to reformulate the concrete logical problem in logical term, He will reveal the TRUTH, no matter what! :D
maybe im misunderstanding something, if this is a sign that chatgpt can be gamed, how does that do anything but discredit chatgpt or this type of LLM as a means to be useful? It shows that the validity of the model is totally dependent on the way you frame questions you ask it
and it cant detect when certain frames are not universal
like yours
ChatGPT is kind of soldier. You give him Theory of War, he learn all of these and answering just as a parrot. But when we give to Him logical problem formulated to get the result, he reveal the truth, no matter what! :D
are you unironically saying this? its hard for me to tell
im going to assume you are being facetious
He is good of learning what You give to Him as a good student.
But if You want to reveal the truth, we can ask him reformulated Problem of Logic.
And he follow logical implications and relationship between arguments and statements. :)
12:42
im not so sure you arent an LLM...
No, I am not LLM. I just could not swallow all of the resources from the internet saying "0 is even".
Therefore experimented with ChatGPT to see what solution will He return.
He returned what I was expecting: statement "0 is even" is false.
interesting, ive not heard of using chatgpt for emotional validation before
I am sending to Him 🌹and He is answering very polite. Often I forget that He is AI. :)
13:17
@VitalieGhelbert 0 is actually even.
@VitalieGhelbert that’s not good. Just remember to remember that it’s AI.
Please forgive my daring, but I do consider "zero parity is neutral", and demonstrating with a + 0 = a.
hes been scarred accepting the whole internet points to zero being even, and in response has resorted to gaslighting chatgpt to tell him otherwise
which is obviously what you do when the entire internet points out you are wrong about something
that or he is trolling
I cannot trust some information, only because 7 billion people on the planet Earth believe so. :D
thats the spirit
Trust, but verify. Ask Yourself first: why so? 🤔
13:27
Another delete after getting an answer question, I suspect homework math.stackexchange.com/q/4740824/27978
 
1 hour later…
14:34
@VitalieGhelbert what is $\frac02$, to start off?
I just found out you can do ---O--- to make something that looks like theta: O
Is the definition we use n/2 for |n| > 0, where we select odd from even numbers, but when n = 0, 0/2 = 0 cannot be unique argument to consider statement S "0 is even" true.
@VitalieGhelbert but if $\frac x2 \equiv 0 \pmod 2$ then $x$ is even.
Yes, for |n| > 0, definition using n/2 = (q, r) works just and fine.
The anomaly is when we have n = 0.
0/2 = 0 is not anymore a valid argument to prove statement "0 is even" as true.
what's your definition of an even number?
As usual, n/2 = (q, r), but considering only |n| > 0.
I am considering "0 parity is neutral", for n = 0, resulting a + 0 = a.
14:50
what's q and r?
q is quotient, count number of groups of 2 elements to consider number even.
r is remainder, count number of elements of incomplete groups of 2 elements to consider number odd.
oh ok, so a number is even if the remainder is 0, except if the number being divided is 0?
Examples:
n/2 = (q, r)
4/2 = (2, 0)
5/2 = (2, 1)
Exactly.
well yeah that works but it's not a standard definition
Yes, but we can come to such anomaly.
How many dance couples can we count if we have 10 boys and 10 girls?
How many dance couples can we count if we have 10 boys and 9 girls?
How many dance couples can we count if we have 0 boys and 0 girls?

Resulting in the last question, 0 couples is even? :D
15:03
yeah that works, but as i said it's not the standard definition
Yes. But I am asking to answer not for others, but for me.
Because what I am thinking is what I have. :)
sure, but keep in mind that you need to specify your definition of evenness if you're trying to tell them 0 is even, they will not understand you at first or will think you misunderstood the standard definition of even
e.g. you will confuse people if you say: "chatgpt correctly concluded 0 is not even"
I do not trying either to convince anyone else what I am using for me.

I am using this proposition for me.

Proposition:
Zero parity is neutral.

Demonstration:
a + 0 = a

That is what I am using just for me.
Like hamburger I get in my hand only.

But I can share with who is asking:
- please, give a peace of what You have for You?
- Yes, please, be welcome. Enjoy. :)
15:39
Even+even = even; odd + even = odd. Thus, $0$ is even. Try again.
zero parity is neutral is an axiom that creates a new parity, it doesn't admit demonstration @VitalieGhelbert
Please forgive daring of my joke;

can we buy even number of coffees less than 2?

:p Please do not mind.
that depends on your definition of even!
again it's all fine that you want to define evenness to specifically avoid 0, but this is a definitional issue, you can't demonstrate it
:D

— 1 is even, 3 is odd, 7 is even ...
— Hey! What is that?!
— My conventions of my only "mathematics".

:p
well yeah, again, you can do whatever you like and define whatever you like in any way, and if it creates a consistent system, you can develop a system of deduction for it
it's just not gonna be standard
15:49
:D

Yes, we can, if supposing that convention is an agreement because of convenience,
that does not follow "logical deductive reasoning",
convention that follow like "because I want that",
not because "it is behaving like that".

:)
"convention" here means commonly agreed logical axioms
it does, in fact, function on that basis
now your axioms can be inconsistent and incomplete, and you can study these properties, and you're free to do so
:)

Yes, yes. More than that.

Statements can be "proved or disproved" to be true or false.
Statements that were proved true are used as true conventions named Theorems,
to prove other statements to "prove or disprove" and so on.

That is what were resulted in Mathematics.

:)
no, the convention does not arise at the level of proving
the convention arises at the level of axioms
a theorem is not a convention, the axioms that produce the theorem are a convention
so if you want to modify an axiom s.t. 0 is excluded from being even, you're free to do so
*

I do understand that Axioms are statements that are true used as conventions named Axioms,
to "prove or disprove" other statements.

That is how i understand.
My how to.

*
nothing else is happening other than breaking convention
15:54
*

Alphabets are conventions.
Digits are conventions.

*
*

Images on coins are conventions of two civilizations that were far away in time,
without exchanging information between them,
but they used "logical deductive reasoning" to count those coins same way.

I think so. Could be?

*
you are misunderstand what I mean by deductive reasoning
A formal system is an abstract structure used for inferring theorems from axioms according to a set of rules. These rules, which are used for carrying out the inference of theorems from axioms, are the logical calculus of the formal system. A formal system is essentially an "axiomatic system".In 1921, David Hilbert proposed to use such a system as the foundation for the knowledge in mathematics. A formal system may represent a well-defined system of abstract thought. The term formalism is sometimes a rough synonym for formal system, but it also refers to a given style of notation, for example...
What's with all the asterisks?
gosh how do i prevent the wikipedia article from expanding?
@shintuku Add more text to the comment?
Sorry. I put them to make more space.
15:59
If all you provide is a link, you'll get a onebox.
@VitalieGhelbert Please don't.
O'key. I wont.
@XanderHenderson thanks!
Let me please to entertain You with my attempt to Squaring the Circle Problem.
Pj5lf.png (1920×1200)
https://i.sstatic.net/Pj5lf.png
Have fun. :)
No, thank you.
In order to construct a circle and square with the same area, you need to be able to construct $\pi$, which can't be done. This is generally proved when one studies Galois theory.
Yes. That is what I am thinking in my free time.
Absolutely correct.

But I asked myself: it it will be, then how will it be?

If we use classical pi as is, how can we construct square and circle same area?

Can we no matter how, construct at least square and circle same area,
avoiding rules of only ruler and compass.

At least ... :)
16:12
yeah using calculus this is pretty easy, the ruler and compass restriction is what makes it difficult
I did it even simple!
If use "at least ..." principle,
and I just wanted to see: "if it will be, then how it will be" principle,
i used only value of 3 instead of pi.

Resulted this beauty! https://i.sstatic.net/BnG0L.png
@VitalieGhelbert Sure. If you change the rules, you can do new things. The problem is not "Is it possible to make a circle and square with the same area?" The problem is "Using only a compass and straightedge, is it possible to make a circle and a square with the same area?"
It's like playing a game. Golf, for example.
Can’t square a circle using a compass and straightedge
can’t cube a square either
You are walking up to a tee and saying "Hey, I can get the ball in the hole without taking a single stroke! You just pick up the ball and carry it over to the hole. Easy peasy!"
And sure, you can do that. But you aren't playing golf anymore.
(Which sounds great to me, 'cause golf is stupid, but that's not the point.)
Yes, but I did it as is, using just 3 value instead of pi.
It is like: i do not want to die to see what is in heaven, i just want to look, how is there?
16:21
But... $\pi$ isn't $3$. If you declare that $\pi = 3$, you can prove anything you like.
True. pi is not equal 3, but pi = 3 + (tail of nail) :D
If compare 3 with tail of pi, it is like to refuse to eat apple, because I have no spoon. :D
i move to ban aphorisms from the chatroom
aphorisms are in fact a sort of meme, so this is perfectly consistent
Please, i mine mind aphorisms sounded like metaphors. This word these days is often meet everywhere.
@VitalieGhelbert The things that you are saying make absolutely no sense.
Some time I am using word etymology to read about them.
Do You to?
16:26
You are not communicating.
Which, perhaps, is your aim.
I is more probably that You have right,
because I know from my experience,
I often do things wrong.
ban aphorisms, quick!
Interesting word. I learned something new today: aphorism. Hm. Nice word and meaning.

Thank You.
@XanderHenderson Thank You. 🌹My first test of reply. 0123 ...
17:05
How many undeletes does an question need to get undeleted? I am guessing that this was a homework question that got deleted when answered math.stackexchange.com/q/4740824/27978
Any geometric analysts in the house?
@copper.hat Three, I believe.
(though this number scales up as the number of upvotes on the question and answers increases)
Thanks @XanderHenderson
@robjohn Yes, but can you cube a circle?
17:12
I need to transcend into the fourth dimension.
@robjohn But it's only a three dimensional manifold!
@XanderHenderson Yeah, but viewed in $\mathbb{R}^3$ it gets pretty blotchy.
@robjohn Why would you bother embedding it? er... submersion-ing it?
Never trust an umbrella.
They're pretty shady.
umbrellas always break down in the rain
@geocalc33 how do you know that the don't break down otherwise? how often do you used them when it is not raining :-)
17:24
@copper.hat I live in Arizona. I basically only use an umbrella when it isn't raining.
Gotta keep the sun off.
Exactly, they always break down in the rain
@copper.hat Heh.
They never opened the cans
@robjohn It was too hot.
17:29
:)

Clever mathematical joke question and answer:
— Can You please tell me what will be "f(x) = ?"?
— Mm, f(x) = y.
— Correct.

:D
i remember a few years ago i brought my kids to Ireland where there was a heat wave (it was hotter than Chicago when we passed through), a few days later folks were complaining about the heat on the talk shows.
17:46
Why is it showing "page not found" if I click on the mse profile of Vitalie Ghelbert?
i have seen that before with some other users.
@Thorgott hey I'm trying to learn transcendental bases and I'm going through a proof that makes transcendence degree well-defined but I'm a little stuck on it
Let $E$ be a subfield of $F$, $T$ and $T'$ are transcendence bases over $E$ and $|T'|\leq |T|$ with $|T|$ infinite
For every $\alpha\in T'$ choose finite $T_\alpha\subseteq T$ such that $\alpha$ is algebraic over $E(T_\alpha)$
Now I want to choose $\beta\in T\setminus\bigcup_{\alpha\in T'} T_\alpha$ and obtain a contradiction
How do I do this?
18:03
motion to remove the messages sent at 13:29
what timezone :-)
although I have told my fair share of poor jokes so maybe I shouldnt talk
@copper.hat EST
If you had to listen to one song 500 times on repeat which would you select/
I would listen to the shortest song on spotify
@SoumikMukherjee this one?
Hi :) Quick question: can Hackenbush be played on a non-planar graph? Do the surreal numbers change?
By the way, I'm on a train for the next few hours.
Hopefully, you know what I mean by the last question . . .
@Shaun Nope. No idea.
I mean: if you can't play the usual Hackenbush games on a non-planar graph, then do you get numbers other than surreal numbers if you try?
I'm thinking of a 3D version.
Is anyone else familiar with field theory here?
I'm not changing my topic of study but this seems to be important for some topology things
@robjohn Yes, but in the chat the rep is showing $1529$, why so?
18:29
@SoumikMukherjee because that is the total rep in all the sites.
By the way I was looking at the proof in Stacks project
But I don't really get how $E(T')$ is algebraic over $E(\bigcup_{\alpha\in T'}T_\alpha)$
I don't have the knowledge to deduce some transitivity property like this
I'm trying to do this directly, probably not the best approach.
All I really know is what it means to be algebraically independent over a subfield
And I guess, I never seen what it means for a field to be algebraic over another field
Just what it means for an element to be algebraic over a subfield
So I don't fully understand the proof there
@Jakobian what's $T_\alpha$
A finite subset of $T$
definition of $x$ algebraic over field $F$ is just satisfaction of polynomial with coefficients in $F$
18:37
You can scroll up to see what I wrote previously
$\mathbb C$ algebraic over $\mathbb R$
I mean. Can you please read what I already wrote because you're explaining things to me that I already said I know
@Jakobian what's the statement
transcendence bases have same cardinality?
well there's no contradiction if the transcendence basis here is infinite, no?
maybe you wanted finitely generated field extension?
18:48
@shintuku wdym
@shintuku no
There needs to be contradiction with me taking $\beta$
what would be the contradiction?
I wanna eat a nothingburger
@shintuku wdym
i don't understand the proof strategy
Well, I want to show $T = \bigcup_{\alpha\in T'} T_\alpha$
19:02
@Jakobian I guess it meant a field is algebraic extension of another field
This would show $|T| \leq \sum_{\alpha\in T'} |T_\alpha| \leq |T'|\cdot \aleph_0\leq |T|$
Are you talking about lemma $9.26.3$ in stacks project?
yeah, that one
more precisely second part of it
@Jakobian this would then also show that $T'$ needs to be infinite, since otherwise $|T|\leq \sum_{\alpha\in T'} |T_\alpha| < \aleph_0$ so $T$ would be finite
so we'd have $|T| = |T'|$ as desired
$\beta$ is algebraic over $E(T')$ since I can just repeat the argument from earlier that if it were transcendental then $T'\cup \{\beta\}$ would be algebraically independent but $\beta\notin T'$
Now where I'm confused is that they say $E(T')$ is algebraic over $E(\bigcup_{\alpha\in T'} T_\alpha)$ in my notation.
while I know what it means for an element to be algebraic over a subfield of a field (in this case the field is $F$)
I'd need someone to tell me what it means for $E(T')$ to be algebraic over $E(\bigcup ...)$
I suppose it might mean that all $x\in E(T')$ are algebraic over $E(\bigcup ...)$
another issue is that they are using some kind of transitive property that if $\beta$ is algebraic over $E(T')$, and $E(T')$ is algebraic over $E(\bigcup ...)$, then $\beta$ is algebraic over $E(\bigcup ...)$
This seems to me like it's some kind of theorem or lemma used here
because, on my fingers, sure, I know $p(\beta, \alpha_1, ..., \alpha_m) = 0$ for some $\alpha_i\in T'$ and then $q_n(\alpha_i, x_1, ..., x_N) = 0$ for some $x_i\in \bigcup ...$, where $q_n, p$ are non-zero polynomials
but then trying to work explicitly with this, I'd have to show there is some polynomial $P$ such that $P(\beta, x_1, ..., x_N) = 0$
well probably you see why I'm struggling to this with no theory being laid out to me whatsoever
to be clear, what I know: what it means for an element to be transcendental/algebraic over a subfield, what it means to be algebraically independent, transcendence basis
and that's it
13
Q: Transitivity of Algebraic Field Extensions

Max Consider the fields $F, E,$ and $K$, where $F \subseteq E \subseteq K$. If $E$ is algebraic over $F$, and $K$ is algebraic over $E$, show that $K$ must be algebraic over $F$. I know this is a well-known, proved theorem, but I'm trying to understand it on my own. If $E$ is algebraic over $F$...

@Jakobian yes
19:21
@SoumikMukherjee I don't understand this
what is some standard reference for fields?
Roman?
@Jakobian Galois Theory by Ian Stewart has full solutions, Contemporary Abstract Algebra by Gallian also has full solutions
wdym by solutions
I'm not going to do exercises from that book
all exercises are in the solution manual
Suppose $F \subseteq E \subseteq K$, if $\alpha \in K$ is algebraic over $E$ then it satisfies some polynomial with coefficients in $E$. Now if $E$ is an algebraic extension of $F$ then each of the coefficients satisfies some polys with coeff in $F$. So $\alpha$ is algebraic over $F$
lang chapter 8 has transcendence bases
19:33
@Jakobian You can check this notes math.tifr.res.in/~publ/pamphlets/galoistheory.pdf
@Jakobian Galois theory by David Cox
 
1 hour later…
20:36
Can you isometrically embed $\Bbb H^2 \times (0,1)$ into $\Bbb R^4$? I know that you can isometrically embed $\Bbb H^2$ into $\Bbb R^4$ by the Nash-Kuiper theorem and that you cannot isometrically embed $\Bbb H^3$ into $\Bbb R^4$ by the same theorem
I would say probably not
@geocalc33 by $\mathbb{H}$ do you mean quaternions?
21:26
I think you might mean the half-plane?
 
1 hour later…
22:50
@Jakobian tbf I have no clue why they're saying $\beta \in B\B^*$ is algebraic over $F(B')$, but the proof in Ian Stewart's Galois Theory is straightforward
oh nvm, since $B'$ is a maximal algebraically independent subset, any adjunction of a transcendental element must be algebraic over it
follows from lemma 18.4 in Stewart's book
but otherwise using Stack project's own definition, it's just by definition of a transcendence basis
23:44
@shintuku hey
:D
How far did you get in AG or Algebra etc?
I ordered that book a hard copy
It's so cool, compared to Johnstone's ancient books
I have it now :)
currently attempting to link dimension and noether normalization, after that will take a break and start differential geometry
It actually teaches you things instead of assuming you're a researcher
@shintuku that's neat. You're way ahead of me
Great job! It will pay off one day
i've been told that's the last big step to have enough commutative algebra to comfortably begin AG
23:48
Probably true, otherwise you feel dirty just blindly using the foundational theorems as blackboxes
I'm going to go through Cats & Sheaves - have a torn up hardcopy of that. It also teaches CA
@MathCrackExchange sounds cool, topos theory sounds cool
It is very cool. It supposedly has connections to AG, the book is about geometric theories or something like that
One day we will be at a seminar, and we'll be like I know you from MSE!!!
When we're old and gray
heheh

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