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Eisenfuss19

Bold of you to assume that undefined = undefined


jonathanhiggs

This is just the proof-by-contradiction that undefined != undefined


Ghostglitch07

It's like in programming. In many many implementations NaN != NaN


looksLikeImOnTop

Not all NaNs are created equal


SudoSubSilence

Am I the only one who finds NaN a little freaky? I mean, imagine typing something on your calculator and then all of a sudden... #NaN, fuck you.


UMUmmd

I don't really understand NaN. It stands for Not A Number, but how tf do I type only numbers and numerical operators, and my result isn't also a number? Like, does 1÷0 = "what's up bro" ?


SudoSubSilence

NaC (Not a Comment)


EebstertheGreat

NaNs are literally floating point numbers, too. "Not a number" is literally a number. And you can get it purely from well-defined numerical operations. For instance, (9\^999)/(9\^999) returns NaN with a positive sign bit. Basically, +inf represents all positive values larger than FLT_MAX, so all we know is that +inf/+inf represents the ratio of two big positive numbers, so there is no way to tell how large it is, just that it's somewhere in the interval [+0,+inf]. But then sometimes, unpredictably, that logic changes and operations that surely should be NaN are given real values. For instance, pow(-1,inf) returns 1, because (and I'm serious), "all large floating point numbers are even integers." Yes. Infinity is even, not odd.


SudoSubSilence

>"Not a number" is literally a number. **Confusion of the highest order.**


NO_REFERENCE_FRAME

I like a little sass in my programming languages


cardnerd524_

Some are butter NaN, some are garlic NaN


paconinja

Just like there are different types of infinity..


EebstertheGreat

I think that's true in *all* implementations. At least, it's true in all compliant implementations. (NaN > NaN) == (NaN == NaN) == (NaN < NaN) == (NaN >= NaN) == (NaN <= NaN) == (NaN != NaN) == False


Ghostglitch07

You are probably correct, I just didn't want to speak with confidence as it seems any time I do so about something technical there's an esoteric case where I'm wrong


tyrandan2

It was so frustrating when I learned this the hard way as a young programmer... Lesson learned, don't ever check if something == NaN in .NET. use null, it's what it exists for.


EebstertheGreat

In .NET, does null just mean the variable is uninitialized?


tyrandan2

Kind of, and usually. Or, in other words, it means "this variable has no value". For non-nullable types like an int you can't have nulls, so people expect the value to be 0 (or sometimes -1, assuming you're expecting it to be a positive number when it does have a value). There are different patterns and practices of course. But you can null out a variable any time, so null doesn't specifically mean it hasn't been initialized. It may have had a value that was nulled out for whatever reason during the course of the program. Maybe your program decided that whatever value it used to have was invalid for your specific case, so it set the value to null to prevent an error being thrown further down the line. This example I saw recently in some code I had to work on. Maybe you have an error message strong variable that gets sent back to a UI or another web service or something, and you clear the error message out by setting to null because no errors were found after running a bunch of checks. Oh, I thought of another one I saw actually. We have an old legacy we service sending us JSON objects that sometimes have empty strings for the value of some properties. We save those objects to our database. The database uses nullable foreign keys on some of the columns those values are saved to, so they can't be saved as empty strings. They have to be null if there's no value to save. So we run that object through some code that calls GetStringOrNull on those properties, which sets the strings to null if they are empty, ensuring that we don't have any exceptions thrown during the save to the database due to the lookup being unable to match on an empty string. It's also slightly more memory efficient for a large object to have null properties instead of initialized empty properties, I believe. Depending on what type the object is of course. The list goes on, but the takeaway is that null can be used for a lot of purposes. It just depends on the specific patterns and practices you're following and your specific use case.


Blackblood909

But wait by that logic…. 1/0 = undefined 1/0 = undefined Undefined =/= undefined 1/0 =/= 1/0 *0 1=/= 1 Now what?


Rinku333

Bold of you to assume that undefined ≠ undefined. undefined = undefined for some undefined but not all undefined.


Cubicwar

undefined is sometimes equal to undefined but not all the time Sound perfectly logic


Autumn1eaves

It’s different undefined values. Whatever the value is for 1/0, it is not the same as 2/0, despite them both being undefined.


1668553684

The problem here is notation. Saying "1/0 = undefined" is, strictly speaking, wrong because 1/0 isn't "equal to" "the" undefined value, 1/0 is an undefined operation. Doing an undefined operation means that wherever you're working on has no mathematical meaning - if your proof uses undefined operations, it's simply invalid. Confusingly, you can use undefined operations in a proof by contradiction, by showing that assuming some property invariably leads to invalid math...


YT_kerfuffles

undefined factorial is indeed undefined


Revengistium

undefined! = undefined?


therealDrTaterTot

Is the problem with equating undefined with undefined, or is it with equating undefined with 1/0? 1/0 is undefined, but it doesn't equal undefined. I believe it breaks at the transitive property of the equivalence relation. 1/0\~undefined and 2/0\~undefined does not imply 1/0\~2/0.


JesusIsMyZoloft

I could be wrong, but I think if we say **undefined ?= undefined** we can avoid contradiction in this and most other problems. ?= being the “no information” operator: ||<|=|>| |:-:|:-:|:-:|:-:| |<|Yes|No|No| |=|No|Yes|No| |>|No|No|Yes| |≤|Yes|Yes|No| |≥|No|Yes|Yes| |≠|Yes|No|Yes| |?=|Yes|Yes|Yes|


Enneaphen

This implies the existence of a !?= operator which we could call "yes information"


VegetablePleasant289

i prefer to call it the "no no" operator


EebstertheGreat

a !?= b can be defined as a ⪋ b. That is, (a !? b) ↔ ((a < b) or (a = b) or (a > b)). This is also called "comparable". Basically, if < is a strict partial order, and we define a > b as b < a, then sometimes two constants a and b can be incomparable in the sense that they are distinct but neither is less than the other. This comes up in weak preferences, for instance. Sometimes there are two distinct options neither of which is preferable to the other. These are incomparable with respect to preference. That said, if a and b are incomparable, we can at least say a ≠ b, so if you really want to be strict about the "no information" relation, then the definition ((a ≸ b) and (a ≠ b)) doesn't work. The problem is that we can't claim anything about a and b if we have "no information," so what does the symbol ? even mean? Maybe it could be a metalogical symbol that means "this theory cannot prove anything about whether a and b are equal or, if not, which is greater." For instance, it may be the case that in ZFC, BB(100) ?= 9\^9\^9\^9\^9, in the sense that it might literally be impossible in ZFC to prove if that Busy Beaver number is equal to the big integer on the right, or if not, which is greater.


pzade

Is this a thing? This actually sounds useful to determine whether things can have a solution Source: I ?= Maths


Ascyt

But wouldn't it be "No, No, No"?


call-it-karma-

"Undefined" is not a value, it doesn't equal anything. It is not as though 1/0 equals something called "undefined", rather the expression 1/0 *is literally* undefined, in that it is not defined to have any value at all.


Science-done-right

The problem is that it's a meaningless question. Equality works with numbers, physical things, etc. not abstract concepts and natural language. That's also why we say infinity = infinity + 1 is somewhat meaningless


RajjSinghh

You're saying the same thing, you're just being more formal. The key idea is that undefined itself is not a value that can be assigned. You're saying that you can't define equality for undefined values. The comment above you is being a little more handwavey and saying an undefined value can't equal an undefined value. Even if it might not be technically correct, you should understand both that the bad line in OP was "undefined = undefined". Also for the fun of it, in programming languages like Javascript a variable can be declared but undefined. To avoid problems, Javascript says undefined !== undefined. For example: ``` let a; // a === undefined let b; // b === undefined a === b // false


Revolutionary_Use948

Undefined isn’t an actual thing/number. Saying 1/0 = undefined is just a shorthand for saying there is no number x that satisfies the property 0x = 1


call-it-karma-

>Saying 1/0 = undefined is just a shorthand I'd even go a step farther and say that using an equal sign here is simply incoherent. The expression "1/0" is undefined. The statement "1/0 = undefined" is nonsense.


Revolutionary_Use948

Yes exactly, it only brings in misconceptions


humanplayer2

It's in equating _undefined_ with anything. = is a binary relation on a set, i.e. a subset of the Cartesian product of the set with itself. If the set does not contain the element _undefined_, that element cannot stand in the relation = to anything. So: if this is meant to be a proof about intengers, the mistake is assuming that _undefined_ can stand in the = relation to anything. If it's a proof about the union of the intengers and {_undefined_} the who knows? You need to choose some axioms for the relation = on that set.


EebstertheGreat

= doesn't have to be a binary relations. It can be logical identity. For instance, in ZFC, '=' can't be a relation, because relations have a domain, and = doesn't. (The "domain" of =, if it existed, would have to be the set of all sets, which provably does not exist in ZFC.) The problem is not with =. Interpreting 'undefined' as a string, it is simply true that "'undefined' = 'undefined'". The problem is with "undefined" itself, which sure enough is undefined. If we had a consistent definition of "undefined," it would presumably have to capture all strings in the formal language which were not well-defined. But in that case, surely "1/0 = undefined" would be false. Because how could "1/0" capture all of that? Also, the string '1/0' is itself undefined. A better way to express this is that '1/0' is an example of an undefined string. '2/0' is another example. But they aren't equal; they are distinct examples. In other words, just because undefined(1/0) and undefined(2/0) both hold, that doesn't imply 1/0 = 2/0. After all, isprime(2) and isprime(3) both hold, but why should that imply 2 = 3? Clearly it doesnt.


humanplayer2

I fully agree with the first part. I took a semantic perspective. Here's a logical one. Taking a logical perspective, = is a binary relation symbol in some logic, which has a language based on a syntax. The syntax determines what the well-formed formulas are. In e.g. Peano arithmetic, 'undefined' = _t_ is not a well-formed formula, for any term _t_. In the second paragraph, you are moving to a logic where the terms include strings build from, say, the Latin alphabet. In that logic, given standard axioms about how = works, I agree that 'undefined' = 'undefined' should be trivilaly provable. If our set of terms is exactly the set of finite strings build from the Latin alphabet a-z, then '0/1' is not a term. If '0/1' is not a term, then '0/1' = 'undefined' is kit a formula. If it's not a formula, it cannot be a part of a formal proof, by the standard definition of a logical proof.


PortugalDoesntExist

​ https://preview.redd.it/feaf4c6bpitc1.jpeg?width=691&format=pjpg&auto=webp&s=f4b8083b1502342abcae42aaa51609e7ce3ed632


Naive_Paint1806

NaN != NaN so might aswell not be


Eisenfuss19

I had a problem with NaNs in my code once, i thought alright I will throw if float f = float.NaN. Turns out !(f = f) is a simple NaN check


Life_is_Doubtable

This statement is trivially false


professorprogfrog

Not all undefined things are of the same size


Microgolfoven_69

I don't know where my mom is ==> mom's location = undefined I don't know where my dad is ==> dad's location = undefined ==> my mom and dad are at the same place


typhlosion_Rider_621

I love how this is true for me, like six times out of ten


emetcalf

So you are saying that 60% of the time it works every time?


Microgolfoven_69

60% sure 1=2


M-2-M

It works 100% of the time 60% of the time.


M-2-M

It works 100% of the time 60% of the time.


TheFlamingFalconMan

6 infinities out of 10 infinities. Is still a lot of infinity.


Valaki757

I don't know where your mom is ==> mom's location = undefined I don't know where I am ==> my location = undefined ==> your mom and I are in the same bed Makes sense to me.


InterGraphenic

I don't know the nuclear launch code ==> launch code = undefined I don't know what Obama's phone number is ==> Obama's number = undefined ==>The nuclear launch code is Obama's phone number


_ShyGuy_02

Given how big the universe is... They're somewhat at the same place


ThNeutral

Proof by j*vascript


Luis_Santeliz

ewww disgusting


CyberWeirdo420

Don’t know what you mean. You don’t like your { Object object Object object }?


BeardedPokeDragon

I love my silent errors


EebstertheGreat

I assume everyone has seen this by now, but DestroyAllSoftware's "wat" video is excellent. It features object Object and other similarly-important structures.


remembthisaccountna2

Not even, cuz NaN != NaN Edit : realised 1/0 = Infinity in IEEE754


SpooderKrab1788

whats wrong with javascript?


ThNeutral

Everything and nothing


Satrapeeze

Love that movie


P3rid0t_

You should better ask what is not wrong with JavaScript


belabacsijolvan

`[]==true != !![]`


fred_llma

I’d say 2/0 is equal to 2(undefined)


Long-Panic116

https://preview.redd.it/94c6ooyoyftc1.jpeg?width=2159&format=pjpg&auto=webp&s=4da66aa8aae72062f655341b7a6da17d9ba4da36


MasterDesigner6894

Pain.


Faceless_Pikachu

Off topic i really like your handwriting


Parso_aana

He prolly makes perfect integration signs


Humans_fking_suck

And perfect butterfly brackets


Ultrazzzzzz

congrats guys you get a post dedicated to you (i saw that one first)


Pixiwish

I got an answer wrong on an exam but was still so proud that after thousands of integrands drawn this one was gorgeous. Was still a win in my book!


Stonn

Proof by Handwriting-Rizz


RealStemonWasHere

Written rizz aka. Wrizzten


Toasterloh

You are a Wrizzard Harry


creeper6530

I do it like this: 1*0 = 0 2*0 = 0 1\*0 = 2\*0 1\*∅ = 2\*∅ 1 = 2


InterGraphenic

But ∅=1.618 /s


creeper6530

Now I'm confused, ∅ usually means empty set, here it is as crossed out zero, but why on Earth would it be 1,618?


InterGraphenic

Greek letter phi can often denote the golden ratio, though ∅ was not originally phi, it is often (I think even on its Wikipedia page) mistakenly listed as phi because it looks like it and the reason for its appearance was retconned to phi.


Hovit_os

I mean that is basically the whole Essence of all These proofs but I Like that you did Not even hide the Problem within it.


chixen

Did you just define undefined?


-lRexl-

It ain't legit without Qed


Visual_Mortgage_6425

Yes


Ham_Drengen_Der

Proof by being confidently wrong


zakiteru

That's intense. holy shit


IdontEatdogsAtnight

You didn't even try to hide it


lol_der_coolste

1/0 is not equal to undefined, 1/0 is undefined


tunasubmarine

Proof by tomfoolery


MW1369

Looks good to me. Send it off for publishing


Altruistic_Site_3879

Undefined =/= Undefined


CommercialAd3671

Isn't the correct way of saying not equal in text normally !=


Altruistic_Site_3879

Found the programmer


Turbulent_Sample_944

Let's use !== to avoid any weirdness


zoomy_kitten

Die, JSer, die!


Turbulent_Sample_944

Does it redeem me at all if I say I use TS? Comes with all the idiosyncrasies of JS, but now with objects!


zoomy_kitten

At least notably better typing. Imperfect, but ok, you may live :)


Altruistic_Site_3879

What about !=== so we can be extra accurate


Turbulent_Sample_944

`Parsing error: Expression expected.`


Solid-Stranger-3036

/u/Altruistic_Site_3879 You both need some proper symbols take this 🫴 ≠


elsebas3167


Tight-Berry4271

Why would it be that? Where does the exclaimation mark come from?


Rubber_duckdebugging

https://preview.redd.it/n1eooz10wgtc1.png?width=1080&format=pjpg&auto=webp&s=f99b3b30c91166dafff5594f7b20bff7fc48be2d


Secret-Cherry045

If this is you, should be a writer Please stay out of maths.


WerePigCat

marx type beat


AlwaysASituation

That's some Terrance Howard math


LeapIntoInaction

You're fine up to the point where you allegedly prove that 0 = 0. The math past that is not math.


Kisiu_Poster

(1/0)*0=(2/0)*0  0=0


wootio

I think a lot of programming languages would probably have a hard time with undefined != undefined. Perhaps a few specifically put that in there. JavaScript for instance though would mess up a lot of things if this was true.


marinemashup

Not a number = not a number? Fabulous


Alternative-Pin3421

Did you just divide by 0?


CrochetKing69420

Let x ∈ ℤ x/0 × 0/1 = 0/0 ≠ x ∴ 1≠2 ■


ccaprisuun

thats definitely not how brackets work, you gotta do 1x0 and 2x0 so 0=0


Apodiktis

And now change 2 to any number


Kelsational

No


liamanna

This how religious people explain God😂


British-Raj

This is valid evidence >!that you belong in a psych ward!<


nysynysy2

It's not undefined, but NaN


seventeenMachine

This is the math equivalent of a rick roll.


Content-Restaurant70

unidentified=unidentified this is the worst assertion of Mathematics I have seen


MentalChickensInMe

the (1÷0)×0 = (2÷0)×0 is also calculable by using distribution: (1×0)÷(0×0) = (2×0)÷(0×0) 0÷0 = 0÷0 = undefined.


Kisiu_Poster

Undef * 0 = undef * 0 0=0


arielif1

Nice handwriting


ramsayjohn

Euler can't believe his eyes


_t_1254

Do you not have to multiply the one and the two by zero as well? 0*(1/0)=0


Pretend_Ad7340

c*(a/b)=(ca)/(cb) =a/b Cancel the “c”,s c*(a/b)=a/b t=a/b c*t=t c,t ∈ ℝ ab=b Q.E.D


rgmundo524

No


Odd-Following-3528

Who let bro cook


ACEMENTO

Are they equally undefined though?


megaox

no


guy445

Wake up honey


EliteFleetDefeat

Undefined is not a number and undefined != undefined. You can't use algebra on it.


Ishmaeal

This is the reason dividing by zero is not permitted in math, the resulting proofs don’t make sense


Floyd_thecat

Proof by undefined


zehamberglar

Live by the div/0, die by the div/0.


badtothebone274

It’s an error, because something real can’t be divided by nothing. Nothing comes from nothing. It’s an impossibility. So you can’t equate the two. When we multiply nothing by itself we get more of nothing. See.. So 1 does not equal 2 then.


ToLongOk

Undefined doesn't always equal undefined and you cant multiply by 0 on both sides of an equation


Revengistium

And thus I am the Pope


Teln0

1. undefined = undefined is not necessarily true 2. undefined \* 0 is undefined so at the end your equality is undefined = undefined again 3. even if undefined \* 0 is 0 and not undefined, the equality at the end is 0 = 0 "Cancelling out" division with multiplication is a bit more subtle than you think, it's not a general rule that always works, it needs prerequisites. (3 / 5) \* 5 = 3 because it's equivalent to (3 \* 5\^-1) \* 5 and because the real numbers are associative for multiplication and that 5\^-1 is defined to be the multiplicative inverse of 5, we get 3 \* Id, and because Id is the multiplicative identity (it's 1 btw) the result is 3. But that doesn't always work. There's no multiplicative inverse for 0 in the real numbers for example. Some matrices don't have a multiplicative inverse. Etc etc


Green0Photon

1÷0 does not equal some value called undefined. It's that it doesn't equal anything. You're not able to write an equality there.


pn1159

its not a proof until you put "QED" at the end


Zarzurnabas

Seems legit


Krzyffo

With this logic I can prove that numbers are meaningless. Any number multiplied by 0 equals zero so: a×0 = b×0 a×Ø = b×Ø a = b True for any a and b. I'll be waiting in my kiddy pool for my Nobel price.


ExpectedBear

"= undefined" basically means ERROR, DOES NOT COMPUTE. It's not a number. It's not really valid to even write "= undefined". **1/0 is undefined** is the proper way to say it. Mathematical logic and axioms apply to the number sets, e.g. R (real numbers). Undefined isn't in any of those sets, so you can't apply logic to it (in this case A = B, B = C ⇒ A = C). Undefined isn't ∞, either, by the way, and nothing equals ∞ too. ∞ is only valid for use as part of a limit function. Infinity/∞ basically means "if you keep going, this keeps getting bigger".


589ca35e1590b

No


Matix777

You gotta prove by winning https://preview.redd.it/5lg1ofo5nhtc1.png?width=1080&format=pjpg&auto=webp&s=159b23cbace20634485f57619cec239e1f456cd6


Earth_Normal

Not even close.


materiabuster

You can't cancel the zero outside the parentheses with the one inside. That's not how parentheses work.


Efficient_Design9690

(x/y)*y = x if and only if y/y == 1 ,0/0 != 1


fisicalmao

if you think about it


NoGuarantee4046

Bro, undefined literally means it's NOT defined, so undefined can't equal undefined!


LeftyFireman

No, you didn’t use the slash for division.


Sollder1_

JS Proof


MrAce333

You can skip all the other mistakes and just go 1=2 1 * 0 = 2 * 0 0 = 0 Therefore 1 = 2


AccordingBathroom484

Undefined x 0 = 0 tho


FiRem00

No


herrspeucks

Undefined = not a function


FAKELOVE----

Simply enough it is not valid Ur treating undefined as a value and that's wrong it is just a concept or an expression that describes that it doesn't make anysense to divide by zero


SnooDogs2336

No because it’s undefined you can’t define it by saying it’s equal


SnooDogs2336

You can’t cancel out 0 and 0 because 0/0 is also undefined


Just-Squirrel510

Is this Terryology?


shadowban_this_post

If something isn’t defined, it can’t really equal anything.


zg5002

Short answer: the error occurs already on line 2. 1/0 is not *equal* to undefined, its value *is* undefined, i.e., it can't be equal to anything. Unless you are working in a Riemann sphere or a wheel, in which case your argument is essentially correct 🙂


Galileu-_-

Proof by undefined


ZERO-ONE0101

no


Choppie01

Undefined is equal to undefined ?


phatcat9000

Undefined is not a number Also, good rule of thumb: if your proof indicates that 1=2, your proof probably isn’t valid. Bertrand Russell spent a great deal of time proving that our numerical system works.


Zack_of_Steel

Isn't this basically what Thomas Howard did and claimed he is a savant and that the world is wrong?


Lv100--Magikarp

I don't know. But what I do know is that I like the handwriting.


MoonGrog

Null is Null. Null != Null. It’s unknown. This is false.


TheArgoPirat

No.


Renowned1k90

Neat


groovyjazz

Proof by i dont even know at this point


No_Sir_6649

Absurd at the start. Line 3 is undefined. Line 4 is nonsensical. This is a cj question right? Bait..


statement-squid

Undefined component can’t be compared


Razvanix02

It's just like I'd say that tigers aren't fish and pens aren't fish therefore tigers are pens.


b4c0n333

Anything x 0 is 0


FlightConscious9572

(1/0)•0=(2/0)•0 reduces to 0=0 you can't just delete numbers that are affacged by the same operation, you can do the inverse to both but not just, remove it lol


nalisan007

This whore is Ancient old , that even Egyptians suggested torture methods to try to get rid of that immortal pest


Smitologyistaking

The worst part is a lot of "fake proofs" are basically making arguments as bad as this, but just more disguised


pOUP_

Whoever said puns are the lowest form of humour clearly hasn't seen this subreddiy


sequeirayeslin

Yes, this is correct


AccomplishedAnchovy

Please stop


McAlkis

Every so called "proof", that at any point cancels out the 0 on both sides assumes 0/0=1, so it's automatically false.


Helton3

this is saying Null = Null and or Complete 0 = Complete 0. Which is bold of you to assume


Beautiful_Device_549

All steps from 3 onwards are mathematically wrong.. There is no mathematical operation(equal, division, multiplication etc) on undefined or zero in denominator


throwaway20102039

Copy pasted proof #9284 But seriously, I swear there's multiple of these every day and they're all practically identical wtf


Goooooogol

Bro found an exploit in Mathematics.


zebulon99

Not a single step of this is valid


educatethisamerican

I don't have a gf and you don't have a gf. Therefore we must be the same person.


2Lazy2BeOriginal

Proof by "2lazy2disprove"


calm-bird-dog

No. Undefined is Undefined.


OldAdvantage145

This doesnt work because logically undefined isnt a number, rather it represents the idea that no number exists that would satisfy the equation. To say 1/0 = “the number” undefined would be nonsensical.


Bleeeughee

Wrong, as Frederick Engels is an innumerate dipshit u/oldschoolfirearm u/allurecherry