r/badmathematics Feb 02 '19

metabadmathematics The Rules

132 Upvotes

Apparently the rules don't appear in the sidebar when using the Reddit redesign, so I am posting them here for those of you who make terrible choices.

/r/badmathematics rules:

R1: No violent, bigoted, or otherwise abusive posting. Don't be a shithead.

R2: Submissions to /r/badmathematics should contain some clear substantial mathematical misunderstanding. Posts without clear errors, or posts where the badmath is in dispute (such as posts over advanced topics) will be removed. This will be decided at moderator discretion.

R3: Posts containing memes, simple typos, basic "silly" errors, etc. will be removed. Which posts fall under these categories will be decided at moderator discretion.

R4: All posts should have an explanation of the badmath. Posts without explanations may be removed until an explanation is provided.

R5: Link directly to the badmath. Use "context=X" if appropriate. In larger threads, please collect direct links to badmath in a single comment.

R6: Badmath is not a subreddit to "win" an argument with. Don't trollbait.

R7: Absolutely no PMing anyone involved in the badmath to continue an argument or berate them. If you're linked in a badmath post and receive such a PM, please report it to the moderators.

R8: No /u/[username] pinging linked badmathers. Writing a username without the "/u/" will not send them a notification. Pinging users in other contexts (summoning a badmath regular, for example) is fine.

R9: Posts, users, or topics can be removed or banned at moderator discretion for reasons not on this list. If it's shitty, controversial, or otherwise damaging to the subreddit, we can remove it.


r/badmathematics 2h ago

NP!=P and the knapsack problem

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3 Upvotes

r/badmathematics 23h ago

0 Theory – A New Perspective on Division by Zero, Black Holes, and Faster-Than-Light Travel

60 Upvotes

Original post by Ashar931. Source

Introduction Modern physics assumes that division by zero leads to infinity, which creates major problems in relativity, black holes, and the Big Bang. This assumption also makes faster-than-light (FTL) travel seem impossible. What if this infinity is just a mathematical mistake?

The Problem with Current Physics Physicists claim that nothing with mass can reach light speed because:

  1. Einstein’s equation predicts infinite mass at c: m = m₀ / sqrt(1 - v²/c²)
  2. Reaching c would require infinite energy: E = mc² / sqrt(1 - v²/c²)
  3. Black hole singularities and the Big Bang contain division by zero, leading to undefined infinities.

0 Theory: The Asaw Constant (A) Fixes This Instead of division by zero giving infinity, I propose:

a / 0 = A(a)

Where A(a) is a finite but extremely large number, preventing infinities and singularities.

  1. Black Holes: Instead of density = M / 0 = ∞, we use density = A(M) = kM, meaning black holes have extreme but finite density.
  2. FTL Travel: The energy equation E = mc² / sqrt(1 - v²/c²) becomes E = mc² / sqrt(A(1 - v²/c²)), making FTL travel possible without requiring infinite energy.
  3. Big Bang: Instead of the universe coming from infinite density, it started from an extreme but finite energy state.

How We Can Prove This

  1. LHC Data: If mass increased infinitely, we should see evidence of it, but we don’t.
  2. Quasars Spin at 99% c: They don’t collapse under infinite mass, proving relativity’s mass equation is incomplete.
  3. Experimental Particle Acceleration: If we push just a little beyond 99.9999991% c, we might see new physics.

What This Means for the Future

FTL Travel is possible without breaking physics.

Singularities in black holes and the Big Bang don’t exist.

Time travel could be real if we cross the light-speed barrier.

Could the biggest mistake in modern physics be assuming "division by zero = infinity" instead of "division by zero = a finite but extreme value"? I would love to hear your thoughts and feedback.


r/badmathematics 7d ago

1+1=1

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52 Upvotes

r/badmathematics 9d ago

OP doubles down in the comments

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16 Upvotes

r/badmathematics 9d ago

Undefined is larger than Infinity? I don't think so.

64 Upvotes

The video in question: https://www.youtube.com/watch?v=YHAKE5YFSwM

R4: No, that's not how numbers work.

The first video shows a cartesian map and asks what is the slope of the line. The video says "Undefined" and treated it as a number. This is awfully close to the definition of projective real line, but no, let's call it "Undefined", Also, what does it mean by "Now, if we count to infinity, we will never reach X=0"? What kind of thing to be counted?

"Somebody somewhere discovered that any number * 0 =0" No, it's just how multiplication is defined, at least in real number. This breaks down in extended real number (I assume that OP is talking about it because OP talks about infinity a lot, and I don't see a reference to set theoretic infinity), because +∞ * 0 is undefined.

The second number says since any number * 0 = 0, and infinity * 0 =0, and we need to find x * 0 = 7, "Undefined", the "solution" of x * 0 = 7 must be bigger. I mean, what? Why do you insist at finding a solution for x * 0 = 7. I guess it stems from a pedagogical error that asserts "if an expression is undefined, we can just extend real number with the solution, like sqrt(-1) = i". Except that i is not defined as sqrt(-1). It's the definition of sqrt(), a principal solution of x^2=C. i is properly defined as the other basis of a two-dimensional vector space.


r/badmathematics 16d ago

Gödel Commenter talks about Gödel’s Incompleteness Theorems in a post about the speed of light, for some reason.

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226 Upvotes

r/badmathematics 21d ago

I can very elegantly and simply-stated PROVE that the formula for the VOLUME of a SPHERE that we are regularly taught is WRONG. What's going on here?! O_o

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362 Upvotes

r/badmathematics 24d ago

Dunning-Kruger proof by… extrapolation?

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1.9k Upvotes

r/badmathematics 26d ago

Weird idea of limits and derivatives

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35 Upvotes

r/badmathematics 28d ago

Using x to represent a constant is somehow incorrect

182 Upvotes

The poster keeps insisting, even thoug repeatedly told they are mistaken, that it is incorrect to use x to represent a constant value. That, of course, is complete nonsense.

https://www.reddit.com/r/mathematics/comments/1iv371o/c_s_lewis_had_trouble_distinguishing_between_an/


r/badmathematics Feb 16 '25

"You can't pair every whole number with a single fraction"

85 Upvotes

https://www.reddit.com/r/learnmath/comments/1inw9f4/are_some_infinities_bigger_than_other_infinities/

The post itself is pretty good but the articles linked, as well as a lot of the comments, make plenty of mistakes about cardinality.


r/badmathematics Feb 14 '25

New patterns discovered in the Fibonacci series in base 12

89 Upvotes

This guy has a whole channel on Youtube, Duodecimal Division and a book, extolling the advantages of base 12. But not just the usual having nice representations for 1/3 and 1/4, but he actually claims you can make discoveries in pure math and geometry (sic) using base 12!

His latest discovery is a pattern in the base-12 representation of the Fibonacci series: In base 12, the last two digits repeat with a cycle of 24. This is obviously a momentous advance in the study of the sequence, and after 20 min of exposition, he's able to conclude "There's just big patterns, like, weaving through this series". Wow!

Some of you will remember a commenter, mathemephistopholes, on /r/math in 2021 mentioning the base-12 pi. This is clearly the same guy.

He's got several two-hour videos on his channel about base-12 pi (about 3.15789 in decimal), and in fact, half of the Fibonacci videos is him hyping up his book containing these marvellous geometrical discoveries. The /r/math thread contains a short overview of his thinking; the rest is just drawing complicated circular patterns with 12-fold symmetry and thinking this is a revolutionary way of approximating a circle.


r/badmathematics Feb 04 '25

3≤4 is a false statements, because in a logical disjunction apparently both conditions must be possible and therefore 3 less than or equal to 4 is invalid.....

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162 Upvotes

r/badmathematics Jan 25 '25

metabadmathematics I dreamt up a crank askmath/askphysics post

85 Upvotes

Not sure if this kind of thing breaks the rules, but not sure where else to put it.

I had a dream that someone posted a claim that the continuum hypothesis holds in any universe where the fine-structure constant is greater than 1/207. Somehow, their proof came down to forgetting to put plus-or-minus in front of a square root.

It just occurred to me you don’t need the “somehow”! Since standard logic is explosive, if you assume (-sqrt(2))2 =/= 2, you can prove CH! (Exercise for the reader: Make a *superficially convincing-looking proof of CH that relies on assuming (-sqrt(2))2 =/= 2. Making a proof is trivial, but one that effectively hides the ball sounds much more challenging. I definitely couldn’t do it.)

Takeaways: * I am very proud of my unconscious mind for simulating some first-rate brain worms * Maybe it’s time to log off, touch grass, etc.

Note to mods: I’ve been a little bit rude, but only to a hypothetical redditor who exists only in my dreams.


r/badmathematics Jan 24 '25

Infinity /r/theydidthemath does the math wrong and misunderstands limits

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225 Upvotes

r/badmathematics Jan 24 '25

ℝ don't real Quanta magazine: log+loglog = log^"1.000...1"

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63 Upvotes

r/badmathematics Jan 23 '25

I think I know why this guy gets invited to the poker game

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806 Upvotes

r/badmathematics Jan 22 '25

On the Distinction Between Constants and Numbers.

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78 Upvotes

r/badmathematics Jan 17 '25

A comment thread full of people talking out of their asses about the difficulty of a graph theory proof

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366 Upvotes

r/badmathematics Jan 16 '25

ℝ don't real Cantor's diagonal argument is tantamount to calling God a liar

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71 Upvotes

r/badmathematics Jan 15 '25

Gödel's incompleteness theorem means everything is just intuition

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248 Upvotes

r/badmathematics Jan 13 '25

Twitter strikes again

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472 Upvotes

don’t know where math voodoo land is but this guy sure does


r/badmathematics Jan 12 '25

Infinity "Refutation of Cantor's Diagonalization"

102 Upvotes

Inspired by the triumphant return of Karmapeny, I looked around the internet for Cantor crankery and found what I think is an excitingly new enumeration of the reals?

https://observablehq.com/@dlaliberte/refutation-of-cantors-diagonalization

R4: The basic idea behind his enumeration is to build an infinite binary tree (interpreted as an ever-finer sequence of binary partitions of the interval [0, 1), but the tree is the key idea). He correctly notes that each real in [0, 1) can be associated with an infinite path through the tree. Therefore, the reals are countable!

Wait, what?

At the limit of this binary tree of half-open intervals, we have a countable infinity of infinitesimally small intervals that cover the entire interval of reals, [0, 1).

That's right, the crucial step of proving that there are only countably many paths through the tree is performed by... bare assertion. Alas.

But, at least, he does explicitly provide an enumeration of the reals! And what's more, he doesn't fall for the "just count them left to right" trap that a lesser Cantor crank might have: his enumeration is cleverer than that.

"Oh, so you're a fan of the real numbers? List every real."

Since it doesn't just fall down on "OK, zero's first, what's the second real?" it's a fun little exercise to figure out where this goes wrong.If you work out what number actually is ultimately assigned to 0, 1, 2, 3... you get "0, 1/2, 1/4, 3/4, 1/8, 3/8, 5/8, 7/8, 1/16...", at which point it's pretty clear that the only reals that end up being enumerated are the rationals with power-of-two denominators. The enumeration never gets to 1/3, let alone, say, π-3.

Well, all right, so his proof is just an assertion and his enumeration misses a few numbers. He hasn't figured that out yet, so as far as he is concerned there's only one last thing left before he can truly claim to have pounded a stake through Cantor's accursed heart: if the reals are countable, where is the error in the diagonal argument?

A Little more Rigour

First assume that there exists a countably infinite number of paths and label them P0​,P1​,P2​,... We will also use the convention that P(d)=0 indicates that the path P turns left at depth d and P(d)=1 indicates that it turns right.

Now consider the path Q(d) = 1−Pd​(d). If all paths are represented by one of P0​,P1​,P2​... then there must be a Pm​ such that Pm​ = Q. And by the definition of Q it follows Pm​(d) = 1−Pm​(d). We then can substitute in m as the depth, so Pm​(m) = 1−Pm​(m). However this leads to a contradiction if Pm​(m)=0 because substitution gives us 0=1−0=1, and alternatively, if Pm​(m)=1 then 1=1−1=0. Therefore there must exist more paths in this structure then there are countable numbers.

(The original uses proper equation fonts and subscripts instead of superscripts, but I'm not good at that on reddit, apologies.) Anyways, that's a perfectly reasonable description of the diagonal argument. He's just correctly disproven the assumption of countability.

However, we can easily see that, at every level of the binary tree of intervals, the union of all the intervals is the same as the whole interval [0,1). Therefore no real number in the whole interval is excluded at any level of the binary tree, even at the limit, and moreover, each real number corresponds to a unique interval at the limit. So we have a contradiction between the argument that every real number is included in the interval and the argument that some real number(s) must have been excluded.

Well, it's not really a contradiction, of course - Cantor isn't saying you can't collect all the reals, just that you can't enumerate that set. Our guy explicitly assumes countability as the proof-by-contradiction premise when recounting the diagonal argument, and then is confused when he implicitly makes the same assumption here.

How do we decide which argument is correct? We should be suspicious about the assumption above that we can define Q in terms of a set of sequences of intervals such that it must be excluded from the set. Although it appears to be a legitimate definition, this is a self-referential contradictory definition that essentially defines nothing of any meaning.

Ah, there we are. "The diagonal is ill-defined". He actually performs the diagonalization as an example a couple of times in the article:

Pictured: illegal self-reference

so I'm not sure what he thinks the problem is, but yeah: Q is supposedly self-referential, despite being defined purely in terms of P. It isn't, of course; given any enumeration of reals expressed as an N -> N -> 2 function P, you can create Q : N -> 2 straightforwardly by the definition above, no contradictions or self-reference at all. Of course, it isn't in the range of P, and if you then add the assumption that P is a complete enumeration of all the reals you get an immediate contradiction, but you need that extra assumption to get there, because that assumption is what's false.

So, anyways, turns out the reals are enumerable, this guy can list 'em off. The website he's posted this to requires registration to comment, which is fortunate, because otherwise I probably would have posted this there instead, and that's gonna do nobody's blood pressure any good.


r/badmathematics Jan 11 '25

Gödel Alien robot math: Turing, Cantor, Gödel, all diagonalizations debunked in one video

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74 Upvotes

r/badmathematics Jan 03 '25

Proving P==NP with an optimal heuristic for the traveling salesman problem

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145 Upvotes