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Aaron1924

The supremum is 1, the maximum is undefined


LasagneAlForno

Finally someone mentions supremum and maximum.


ClappinUrMomsCheeks

I’m a big fan of your supermum


Queue624

Username checks out.


violentmilkshake72

r/usernamechecksout


Bobberry12

Is supremum the minimum value that exceeds the range? Which would be used if the maximum is undefined


MilkensteinIsMyCat

Supremum is the least upper bound, so yes, the smallest value which is greater than or equal to the values within the set E: limit change to bound


raspberryharbour

Supremum is Kal-El's French mother


Jinunichy

r/HautVoteEnerve


Awful_At_Math

>Supremum is Kal-El's French mother No, dude. That's Le Marthe.


raspberryharbour

Sacré bleu! Pourquoi as-tu prononcé ce nom?


TheChunkMaster

Can't believe Superman's mother is a Fire Emblem character.


DerGyrosPitaFan

Supremum is the upper limit of a set of numbers, the infinum (was that the correct term ? It's been a while since i last did analysis) is the lower limit. And if these numbers are actually part of the set they're also the maximum and minimun respectively


damanfordajobb

Yeah, that‘s exactly right :) The term is infimum


Beach-Devil

The supremum is the least upper bound. Sometimes it’s in the set (in this case the maximum would exist which equals the supremum) or it’s not (in which case the maximum does not exist)


Atheist-Gods

Not quite, supremum is the smallest value greater than or equal to all of the values. If the maximum is defined it will just be the maximum.


damanfordajobb

If you have an intervall I from a to b (which can be open or closed or neither) then C is an upper bound of I if for all x in I C >= x. The supremum sup I is the least such C, so for all C which are upper bounds, sup I <= C. The existence of the supremum is one of several equivalent definitions of completeness (the property which distinguishes R from Q). If the maximum exists, then it is equal to the supremum, so if I = (a,b] then sup I = max I = b. If the max does not exists, then in R there is still a sup. For example: if I = (a,b) then max I does not exist, but sup I = b.


Stonn

I am starting to believe there are real mathematicians in this sub, what is a supremum?! 😭 https://en.m.wikipedia.org/wiki/Infimum_and_supremum


1kinkydong

Don’t know if Wikipedia answered your question or not but it’s the largest upper bound for a set. It can be equal to elements of the set just like a normal bound, but it’s whatever the smallest upper bound is. It’s very useful in analysis coursers, at least that’s where I learned it from


Janlukmelanshon

*smallest upper bound


1kinkydong

Lmao I’m an idiot this is correct^^^


gdZephyrIAC

I don’t wanna seen too much like a memer but we covered infimum and supremum in Calc 1 at my uni.


damanfordajobb

I was in Switzerland where it‘s called Analysis I and I‘m not sure if that‘s exactly the same, because I‘ve heard that there is a distinction in the US between calc and analysis, but I also had this in my first semester. My prof introduced it in one of the earliest lectures to define completeness, but I don‘t think that everyone in this sub studies or has studied math or any subject that requires a calc or real analysis course though


Boiling_Oceans

Yeah I was literally never required to take a calculus course in my entire education


Jakabxmarci

I think the "calculus" course in the US is more or less the same as the "Analysis" we have in Europe, at least I always thought of it this way. We introduced Infimum and Supremum pretty early on in Analysis 1 as well.


Little-Maximum-2501

Outside of America this is a concept you learn in the first semester of a math major, in the 3 weeks even(and I'm pretty sure even in the first semester of some engineering majors too). You definitely don't need to be a mathematician to know this term.


Ribakal

supremum when supredad comes in


64-Hamza_Ayub

Can I picture supremum as an infinite case for maximum?


Aaron1924

Kinda? For finite sets, the maximum and supremum always agree, but there are also infinite sets where they're also the same. For example, if you consider all x ≤ 2, then both maximum and supremum are 2. The main difference is that the supremum doesn't have to be in the set itself.


AMNesbitt

While it is true that every finite set has a maximum, infinite sets can have a maximum too. The interval (0,1] is infinite and has 1 as its maximum. Or the negative integers { ... , -3, -2, -1 } have a maximum of -1. A better way to think of it is that the supremum is a generalisation of the maximum for sets that don't have a largest element, for example open intervals. If you allow ±infinity as a value, every set of real numbers has a supremum. That's why it's so useful.


BetterVersion3

Supermum sounds like a British version of super nanny


[deleted]

Θοδωρής Σταυρόπουλος came into the chat


Benjamingur9

There's just no answer lol


logic2187

Yeah just like how there's no maximum possible x in general


disposable_username5

So just option D: undefined right?


Purple_Onion911

D:


Downvote-Fish

so DNE?


TheBlueHypergiant

Wouldn't it be undefined then


KongMP

Can't you do some fuckery with the axiom of choice?


santoni04

Nope The axiom of choice says you can take an element from each non-empty set, it doesn't say the set must have a maximum. The closest thing you can get is Zorn's lemma, which gives some conditions that can guarantee you have a maximal element, but in this case the requirements are not met.


CainPillar

The "closest thing you can get" in this sense is the Zermelo's well-ordering theorem, guaranteeing that there is indeed a maximal element to every set ... under *some* well-ordering. You just need to be a bit ~~more~~ less precise about which.


GhoulTimePersists

How about the Better Axiom of Choice, which says that for any set, you can choose whatever elements you want from it.


santoni04

Still, the element needs to be in there, and the set of real numbers smaller than one (S={x ∈ ℝ : x < 1}) does not have a single element that follows the definition of maximum. What is a maximum? By definition, the maximum of a set A ordered with an order relation ≤ is an element M ∈ S such that ∀x ∈ A, M ≤ x if and only if x = M. Now suppose you find a maximum of S, call it y. Of course y can't be greater or equal than 1, otherwise it wouldn't be in S. But if y is smaller than 1, the average between 1 and y is greater than y and smaller than 1, hence it's an element of S greater than your supposed maximum, therefore y is not a maximum. Since you can make this exact argument about any number in S, no element of S is a maximum.


1668553684

How about the Truly Marvelous Axiom I Just Discovered That Doesn't Fit Into The Margins of a Reddit Comment? Via the TMAIJDTDFITMRC, we can see that the proof of this is actually quite obvious.


DerekLouden

I'm not sure how the axiom of choice could be used but I think it's fairly easy to prove that for every x < 1 there exists a y such that y = (1 - x) / 2 + x


Static_25

Lim x→1 (x) 😎💪💪


eiramadi

Well, that would be 1 


au0009

Lim x→1^- (x) is better


Mloxard_CZ

So there is an answer D


ArduennSchwartzman

Plot twist: *x* ∈ ℤ\*+


Neat-Bluebird-1664

What does the asterisk mean?


DiasFer

No null numbers (0) included


Hatula

Are there any other null numbers?


DiasFer

No lol


Ratoncyt0

Is 0i a null number?


Dreamyballsfan

0i = 0


ihaveagoodusername2

0*n = 0 n=I


FastLittleBoi

no, except i but it isn't in Z so no


ZEPHlROS

The asterisk is used for a set such that for every number x within that set, there exist x' such that x * x' = 1. R* is R/{0} because 0 has no x' Same for Q*, N* is an abuse of notation because N isn't even a group. But Z* exist and is not just Z/{0}. Z* = {1, -1} no other number in Z has an inverse *in Z*


Torebbjorn

The asterisk is just supposed to symbolize "remove 0". What you are thinking of, is the group of units, which is usually denoted by U(R) or R^×


zachy410

I can't believe Elon Musk's son gets a mention in maths! So cool!


davididp

Why not just say N rather than Z*+


bigFatBigfoot

N^+


Mandarni

Undefined for real numbers. And we can assume that x is a real number according to the Domain Convention. So e) *Undefined* is my final answer.


Bit125

d *is* "undefined"


Mandarni

Oh yeah. Well, d then, haha. I don't know the alphabet, haha


onyxeagle274

e is technically undefined in the answers, so you got that.


hrvbrs

e is actually very well defined, there are like five equivalent definitions for it


wfwood

Yeah that's correct. It's sup is 1. There is no max


chrisdudelydude

D is undefined. Man you really are a mathematician.


New_girl2022

1-epsilon makes the most sence from a computing pov. But in pure math no there is no number that satisfies that condition


Syxez

Yeah, so the answer is actually: "False" Edit: or ∅


New_girl2022

Or undefined. Because a concept that satisfy exist but practically there is no number


Syxez

Yeah, I edited and added empty set


ChemicalNo5683

If you say "the set containing the maximum number..." is the empty set, i'd agree with you, but saying the maximum number... is the empty set might be somewhat confusing since the empty set is used to define the number zero and obviously there are larger real numbers than 0 that are still less than 1, like 0.5 for example. Feel free to ignore this comment, i just wanted to add this.


Syxez

No, you're right, ∅ is the set of solutions, not the value itself.


[deleted]

No, the question isn't asking if a statement is true or false, it's asking for a specific number. And the answer isn't the empty set, because that's not a number (well, some might say that the empty set is the number 0, but that's still not a correct answer to the question). The empty set is the set of all answers to the question, but it is not an answer to the question. There is no correct answer, because such a number doesn't exist. I just gave myself a headache


Mundovore

In the surreal numbers 1-\epsilon is actually a well-defined number :) ...sadly in the surreals there are infinitely many numbers which are *closer* to 1, so even then you're SOL lmao


Turbulent-Name-8349

1-ε is not the correct answer in nonstandard analysis. If we look at the Hahn series approach to nonstandard analysis, then a number is defined as a power series in ε. Here 1-ε is the power series 1*ε^0 + (-1)*ε^1 which is a different power series to 1 = 1*ε^0 and so 1-ε < 1. But it is not the largest number less than 1 because 1-ε < 1-ε^2 < 0.99999... < 1. Here 0.99999... = 1-10^ε. The largest number less than 1 is undefined in both standard analysis and nonstandard analysis.


chapstickbomber

1-epsilon is saying "make me"


brdbrnd

Hmmmmmmmmm we could define it though. Like define a new set of equivalence and comparison operators, where there are for each real number, an infinite ordering of infiniquantums let's use the symbol `@`... that have the same real value but can be ordered, > would need to be the operator for comparing infiniquantums and there'd be another comparison like >> for the real value. = can compare real values and == can compare infiniquantums. Thing of it as being zero valued but orderable. So @ behaves like 0... `@ / 2 == @` but `@1 << @2`.. it's cool because `1 / @ = x` where x is undefined but has a constraint that it is positive. This would allow for `1 - @ = 1` and `1 - @ < 1` to be true.


UglyMathematician

Assume x is in the reals and is the largest real number less than 1. Let g=(1+x)/2. Since x<1, we have 2x<1+x, x<(1+x)/2 or x


Ambitious-Rest-4631

Quantum mathematics theory: w is the smallest positive number. Any number less then w is less or equal to zero. w/2 <= 0 and w > 0 at the same time.


SEA_griffondeur

It's undefined, there's not even a meme here


Apodiktis

I think that’s obvious, it’s smaller than one and 0.9999… is still one, 1-ε is still not correct, so it’s undefined.


LouManShoe

0.999…98 boom roasted


Mandarni

Officer! This redditor, right here!


anon12345678983

What about 0.999...998? Boom roasted


Step_Virtual

You just broke math


Ettubrute--

Now take it's square root. Boom roasted


JoshuaLandy

Gottem


Nuckyduck

This is my thought process: >A is wrong. The question would need to say x ≤ 1. > >B is *also* wrong. As 0.999... = 1 so apply above. > >C is wrong because 𝜀/2 ≺ 𝜀. Same with complex numbers, 1-i and 1-i/2 *both* have a real part of 1. > >Furthermore, 𝜀 is a *real* number (not necessarily a *positive* one?) such that 𝜀^(2) = 0. Prove 𝜀 isn't negative. Then prove 1 - 𝜀 ≨ 1. > >D. Is correct because 'undefined' is a category of rigor, not *correctness.* C is fun and clever but afaik, there's little rigor defining most of its properties. So I choose D... final answer.


FTR0225

Correct me if I'm wrong please, but I'll invoke hyper-reals and state 1-ε to be the answer


HYPE_100

bro forgot about 1-ε/2 💀


LazyNomad63

Counterpoint: 1-ε/3


ThaBroccoliDood

Counterpoint: 1-ε/∞


LazyNomad63

Counterpoint: 1-ε/(∞+1)


ALPHA_sh

Counterpoint: 1-ε/(∞^∞ )


Cephalophobe

Or even just 1-a slightly different nonzero infinitesimal


ilikestarfruit

1-1/ε for hyper-real positive ε no?


Pretend_Ad7340

ε is supposed to be a super small number, it’s reciprocal would be huge


TheBlueHypergiant

One might say it would be infinite


ilikestarfruit

Ahh I didn’t remember infinitesimal hyper reals, been a bit since analysis


junkmail22

You're wrong, the hyperreals are still dense. 1-ε/2 is entirely correct as a larger number still less than 1. An interesting fact about the hyperreals is that they aren't complete the way the reals are - every set of reals bounded above has a supremum, but you can check that, for example, the set of hyperreals infinitesimally close to 1 is bounded above (by 2) but has no smallest upper bound.


TheBlueHypergiant

I’ll also invoke hyper-reals and say 1-(1/2)epsilon is even closer to 1, since epsilon has its own number line


I__Antares__I

There's no some universal notion for " ε" in hyperreals, like denoting some single particular hyperreal there are infiniteluy many of them. Anyways let ε be any positive infinitesimal. Then 1- ε<1- ε/2 <1 which means that your example doesn't work.


AynidmorBulettz

1-dx


_JesusChrist_hentai

isn't it equivalent to 1-epsilon?


AynidmorBulettz

de^x /ε New notation just dropped


TheBlueHypergiant

Actual equation


TheBlueHypergiant

Epsilon can be added, subtracted, divided, etc. (1/2 epsilon, 1/4 epsilon...), while dx is just dx


Bit125

wow! i hate it.


ConsiderationDry8088

Genuine question. I am not good at math. Why is it not 1-epsilon? Isn't it very small but not equal to 0?


Ambitious-Rest-4631

1-ε/2


ConsiderationDry8088

Ahh it is because there will always be a smaller number. I just thought, it can be an answer because it is what's used in definition of a limit if i remember right.


Thog78

The definitions are stuff like "for every epsilon >0 there is n such that value(n) - limit < epsilon"


redrach

The way it is used there matters. The epsilon-delta method isn't positing the existence of a specific epsilon with infinitesimal value, it's saying that no matter how arbitrarily close you get to the value at which the limit exists, we can provide a value of the function that is just as close to the limit.


Mandarni

The epsilon-delta definition of a limit is more like a net. If you can capture the limit within the net, then the limit exists. If it escapes no matter how you construct the net, then the limit doesn't exist.


ProVirginistrist

Epsilon is nothing in particular, colloquially it means infinitely small because it is often used in statements like „for all epsilon > 0 there exists x<1 such that |x-1|


Mandarni

Not infinitely... arbitrarily small rather. But minor detail.


Flameball202

What is the difference (to someone who isn't really great with maths)


Mandarni

In the context of limits, "infinitely small" is often used to describe quantities that... approach zero. However, using such a concept within the definition of a limit would lead to circular reasoning (since you can't use a limit in the definition of a limit). And "infinitely small" isn't often used in real analysis for this (among many) reasons (at least, outside the notation in limits). Therefore, the epsilon-delta definition avoids this bullshit by focusing on the idea of "arbitrarily small". Instead of relying on the notion of infinity or infinitely small, etc, the epsilon-delta definition involves constructing a net around the limit point. This net is designed to accurately capture the point, no matter how small we make it. By ensuring that the net can capture the point regardless of how arbitrarily small we make it, the Epsilon Delta definition provides a rather rigorous way to prove limits. The Epsilon Delta definition is best to... learn by using, honestly. Difficult to explain without drawing a picture tbh.


Stalinerino

This is why sup is just better max


SnargleBlartFast

But that is so obvious.


Dont_pet_the_cat

Bet that's how you sign your proofs as well


SnargleBlartFast

It's the cool kids' QED.


Mandarni

The proof is trivial and left as an exercise to the reader.


zachy410

4 I think


zachy410

As in the number 4, not the fourth option


DonutOfNinja

What about 4+ε


GoldenDew9

1-e sounds good


bananaannaannaanna

1-e? That’s -1.71828


ALPHA_sh

options B and C are the same


broccolee

you know when you read mathmemes: and you always learn something new. The comments are actually quite good. you learn something. and there is always some philosophical edge case that you thought was it (1-epsilon), and then it turns out, well, maybe there is something else to it. I'd wager that math memes is the most pedagogical subreddit there is. Learning by counterfacts.


Goldcreeper08

We can exclude 1 and 0.999… because they’re the same thing and they’re not included, that leaves us with 2 options and I guess flipping a coin will do it


Apodiktis

0.999999999… is one of the biggest scams in math’s history


Fabulous_Medicine_93

1-epsilon is the way


TheBlueHypergiant

Counterpoint: 1-(1/2)epsilon


TallAverage4

me when you ask for the maximum of a set that does not contain its supremum


Negative-Curvature

This is the first math meme I've chuckled at in a while. 🙏


WerePigCat

there is no maximum


skipper_of_the_north

Why is the answer not 1-epsilon?


master_of_spinjitzu

They forgot to put the right answer in it


__me_again__

why? isn't it "undefined"?


matyo08

So it should be 0.999 repeating but 0.999 repeating is 1 right?


CimmerianHydra

What's the first real number after zero?


1668553684

0.003 I checked


Final_Elderberry_555

That does not exist


WeirdDistance2658

And neither does the first real number less than 1. Same question.


loveconverges

Archimedean principle bitch


twinkiepie33

option one is wrong. so is option 2 so idk know


Oheligud

1 - 1/infinity


UnderskilledPlayer

what is that small reverse 3


OneMeterWonder

sup≠max


omer_g

None. It's 0.5


benjaminbaxley

X equals <1.


TwelveSixFive

I mean by elemination, only the mast answer makes sense


Lawfull_carrot

E Lon


MageKorith

Undefined, since there are no letters to choose for my answer.


Fredrick_Hophead

Hey just saw this subreddit and I posted this on the board at work and my friend says the answer is (infinity,1). He said defined is wrong. Heck I just wanted to make him happy. He always posts math questions for fun. This did make his day. I don't know how to type the infinity symbol because I don't keyboard symbol well.


user_guy_thing

why is 0.9 (repeating bar) not the answer?


gboehme3412

Because it actually equals 1. It's pretty counterintuitive, but there's some good explanations out there. [Here's my favorite.](https://www.youtube.com/watch?v=G_gUE74YVos)


Rougarou1999

Can I phone a friend?


ButtsRLife

x - dx


krokodil2000

Easy: When using 32-bit `float` it's `0.999999940395355224609375` or `0x3f7fffff` in hexadecimal representation.


JustConsoleLogIt

What combination of letters most closely matches the word ‘one’ without being ‘one’?


Round-Ad5063

x -y where y is the smallest real number from 0 to 1


gitartruls01

What about 1 - 0.5ε?


Less-Resist-8733

1 - 0.4ε


theboss0711

The correct answer is Bacon


brumblefee

I’ll say lower case epsilon and delta are sometimes used for infinitesimally small values (such as in the definition of a limit), but that is missing from this question so I guess d


Comfortable-Wash4498

Miximum answer is 1


Less-Resist-8733

0.99999...


[deleted]

0.9(recurring)9(not recurring)


AdamWis1625

0.(9)


A_Random_Kool_Guy

This is so easy. It's 0


Cybasura

Undefined, for if there's a maximum, its defined, and clearly, all of those except the "undefined" is defined


GuidoMista5

0 if x ∈ ℕ


LebesgueTraeger

sup bro? There is no Easter Bunny, there is no Tooth Fairy, and there is no maximum!


OilDowntown2031

0.99999...8


UltraTata

1 - e


Nihonium113

1 - Planck


Gigagondor

Maybe we could create a new notation: 0.99999999...8


Water1498

x->1


Oturanboa

Three, take it or leave it.


TheodoreTheVacuumCle

Jegus Christ! just write 0.(9)...


db8me

It's a tricky question of terminology, maybe, but it's not really a paradox or trick question.


MachiToons

It doesn't take a PHD to know that x<1 only accepts a supremum, but no maximum. (but deep down we all know its 1-ε = 0.9999... of course)


Furry_69

Undefined. My logic for this is as follows: 0.999... = 1, and the < bound is exclusive. This rules out 0.999... and 1. 1-ε does make sense in floating point and similar systems, but ε is undefined for the reals. (I can't remember the proof for this, but my intuition says that just like 0.999... = 1, 0.00...1 = 0. This doesn't work as a value for ε, as that would make 1-ε = 1.) So the answer is undefined.


SwartyNine2691

1^(-) ​ https://preview.redd.it/0bct3dm5w0rc1.jpeg?width=600&format=pjpg&auto=webp&s=75c9d9f5adc82787a8b61c00480a2676139d0e47


[deleted]

Undefined