Archive for the 'Bad Algebra' category

Bad Math from the Bad Astronomer

Jan 17 2014 Published by under Bad Algebra, Bad Math, Bad Physics, Obfuscatory Math

This morning, my friend Dr24Hours pinged me on twitter about some bad math:

And indeed, he was right. Phil Plait the Bad Astronomer, of all people, got taken in by a bit of mathematical stupidity, which he credulously swallowed and chose to stupidly expand on.

Let's start with the argument from his video.

We'll consider three infinite series:

S1 = 1 - 1 + 1 - 1 + 1 - 1 + ...
S2 = 1 - 2 + 3 - 4 + 5 - 6 + ...
S3 = 1 + 2 + 3 + 4 + 5 + 6 + ...

S1 is something called Grandi's series. According to the video, taken to infinity, Grandi's series alternates between 0 and 1. So to get a value for the full series, you can just take the average - so we'll say that S1 = 1/2. (Note, I'm not explaining the errors here - just repeating their argument.)

Now, consider S2. We're going to add S2 to itself. When we write it, we'll do a bit of offset:

1 - 2 + 3 - 4 + 5 - 6 + ...
    1 - 2 + 3 - 4 + 5 + ...
1 - 1 + 1 - 1 + 1 - 1 + ...

So 2S2 = S1; therefore S2 = S1=2 = 1/4.

Now, let's look at what happens if we take the S3, and subtract S2 from it:

   1 + 2 + 3 + 4 + 5 + 6 + ...
- [1 - 2 + 3 - 4 + 5 - 6 + ...]
   0 + 4 + 0 + 8 + 0 + 12 + ... == 4(1 + 2 + 3 + ...)

So, S3 - S2 = 4S3, and therefore 3S3 = -S2, and S3=-1/12.

So what's wrong here?

To begin with, S1 does not equal 1/2. S1 is a non-converging series. It doesn't converge to 1/2; it doesn't converge to anything. This isn't up for debate: it doesn't converge!

In the 19th century, a mathematician named Ernesto Cesaro came up with a way of assigning a value to this series. The assigned value is called the Cesaro summation or Cesaro sum of the series. The sum is defined as follows:

Let \(A = {a_1 + a_2 + a_3 + ...}\). In this series, \(s_k = Sigma_{n=1}^{k} a_n\). \(s_k\) is called the kth partial sum of A.

The series \(A\) is Cesaro summable if the average of its partial sums converges towards a value \(C(A) = lim_{n rightarrow infty} frac{1}{n}Sigma_{k=1}^{n} s_k\).

So - if you take the first 2 values of \(A\), and average them; and then the first three and average them, and the first 4 and average them, and so on - and that series converges towards a specific value, then the series is Cesaro summable.

Look at Grandi's series. It produces the partial sum averages of 1, 1/2, 2/3, 2/4, 3/5, 3/6, 4/7, 4/8, 5/9, 5/10, ... That series clearly converges towards 1/2. So Grandi's series is Cesaro summable, and its Cesaro sum value is 1/2.

The important thing to note here is that we are not saying that the Cesaro sum is equal to the series. We're saying that there's a way of assigning a measure to the series.

And there is the first huge, gaping, glaring problem with the video. They assert that the Cesaro sum of a series is equal to the series, which isn't true.

From there, they go on to start playing with the infinite series in sloppy algebraic ways, and using the Cesaro summation value in their infinite series algebra. This is, similarly, not a valid thing to do.

Just pull out that definition of the Cesaro summation from before, and look at the series of natural numbers. The partial sums for the natural numbers are 1, 3, 6, 10, 15, 21, ... Their averages are 1, 4/2, 10/3, 20/4, 35/5, 56/6, = 1, 2, 3 1/3, 5, 7, 9 1/3, ... That's not a converging series, which means that the series of natural numbers does not have a Cesaro sum.

What does that mean? It means that if we substitute the Cesaro sum for a series using equality, we get inconsistent results: we get one line of reasoning in which a the series of natural numbers has a Cesaro sum; a second line of reasoning in which the series of natural numbers does not have a Cesaro sum. If we assert that the Cesaro sum of a series is equal to the series, we've destroyed the consistency of our mathematical system.

Inconsistency is death in mathematics: any time you allow inconsistencies in a mathematical system, you get garbage: any statement becomes mathematically provable. Using the equality of an infinite series with its Cesaro sum, I can prove that 0=1, that the square root of 2 is a natural number, or that the moon is made of green cheese.

What makes this worse is that it's obvious. There is no mechanism in real numbers by which addition of positive numbers can roll over into negative. It doesn't matter that infinity is involved: you can't following a monotonically increasing trend, and wind up with something smaller than your starting point.

Someone as allegedly intelligent and educated as Phil Plait should know that.

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Genius Continuum Crackpottery

Mar 21 2013 Published by under Bad Algebra, Bad Logic, Bad Math, Cantor Crankery

There's a lot of mathematical crackpottery out there. Most of it is just pointless and dull. People making the same stupid mistakes over and over again, like the endless repetitions of the same-old supposed refutations of Cantor's diagonalization.

After you eliminate that, you get reams of insanity - stuff which
is simply so incoherent that it doesn't make any sense. This kind of thing is usually word salad - words strung together in ways that don't make sense.

After you eliminate that, sometimes, if you're really lucky, you'll come accross something truly special. Crackpottery as utter genius. Not genius in a good way, like they're an outsider genius who discovered something amazing, but genius in the worst possible way, where someone has created something so bizarre, so overwrought, so utterly ridiculous that it's a masterpiece of insane, delusional foolishness.

Today, we have an example of that: Existics!. This is a body of work by a high school dropout named Gavin Wince with truly immense delusions of grandeur. Pomposity on a truly epic scale!

I'll walk you through just a tiny sample of Mr. Wince's genius. You can go look at his site to get more, and develop a true appreciation for this. He doesn't limit himself to mere mathematics: math, physics, biology, cosmology - you name it, Mr. Wince has mastered it and written about it!

The best of his mathematical crackpottery is something called C3: the Canonized Cardinal Continuum. Mr. Wince has created an algebraic solution to the continuum hypothesis, and along the way, has revolutionized number theory, algebra, calculus, real analysis, and god only knows what else!

Since Mr. Wince believes that he has solved the continuum hypothesis. Let me remind you of what that is:

  1. If you use Cantor's set theory to explore numbers, you get to the uncomfortable result that there are different sizes of infinity.
  2. The smallest infinite cardinal number is called ℵ0,
    and it's the size of the set of natural numbers.
  3. There are cardinal numbers larger than ℵ0. The first
    one larger than ℵ0 is ℵ1.
  4. We know that the set of real numbers is the size of the powerset
    of the natural numbers - 20 - is larger than the set of the naturals.
  5. The question that the continuum hypothesis tries to answer is: is the size
    of the set of real numbers equal to ℵ1? That is, is there
    a cardinal number between ℵ0 and |20|?

The continuum hypothesis was "solved" in 1963. In 1940, Gödel showed that you couldn't disprove the continuum hypothesis using ZFC. In 1963,
another mathematician named Paul Cohen, showed that it couldn't be proven using ZFC. So - a hypothesis which is about set theory can be neither proven nor disproven using set theory. It's independent of the axioms of set theory. You can choose to take the continuum hypothesis as an axiom, or you can choose to take the negation of the continuum hypothesis as an axiom: either choice is consistent and valid!

It's not a happy solution. But it's solved in the sense that we've got a solid proof that you can't prove it's true, and another solid proof that you can't prove it's false. That means that given ZFC set theory as a basis, there is no proof either way that doesn't set it as an axiom.

But... Mr. Wince knows better.

The set of errors that Wince makes is really astonishing. This is really seriously epic crackpottery.

He makes it through one page without saying anything egregious. But then he makes up for it on page 2, by making multiple errors.

First, he pulls an Escultura:

x1 = 1/21 = 1/2 = 0.5

x2 = 1/21 + 1/22 = 1/2 + 1/4 = 0.75

x3 = 1/21 + 1/22 + 1/23 = 1/2 + 1/4 + 1/8 = 0.875


At the end or limit of the infinite sequence, the final term of the sequence is 1.0


In this example we can see that as the number of finite sums of the sequence approaches the limit infinity, the last term of the sequence equals one.

xn = 1.0

If we are going to assume that the last term of the sequence equals one, it can be deduced that, prior to the last term in the sequence, some finite sum in the series occurs where:

xn-1 = 0.999…

xn-1 = 1/21 + 1/22 + 1/23 + 1/24 + … + 1/2n-1 = 0.999…

Therefore, at the limit, the last term of the series of the last term of the sequence would be the term, which, when added to the sum 0.999… equals 1.0.

There is no such thing as the last term of an infinite sequence. Even if there were, the number 0.999.... is exactly the same as 1. It's a notational artifact, not a distinct number.

But this is the least of his errors. For example, the first paragraph on the next page:

The set of all countable numbers, or natural numbers, is a subset of the continuum. Since the set of all natural numbers is a subset of the continuum, it is reasonable to assume that the set of all natural numbers is less in degree of infinity than the set containing the continuum.

We didn't need to go through the difficult of Cantor's diagonalization! We could have just blindly asserted that it's obvious!

or actually... The fact that there are multiple degrees of infinity is anything but obvious. I don't know anyone who wasn't surprised the first time they saw Cantor's proof. It's a really strange idea that there's something bigger than infinity.

Moving on... the real heart of his stuff is built around some extremely strange notions about infinite and infinitessimal values.

Before we even look at what he says, there's an important error here
which is worth mentioning. What Mr. Wince is trying to do is talk about the
continuum hypothesis. The continuum hypothesis is a question about the cardinality of the set of real numbers and the set of natural numbers.
Neither infinites nor infinitessimals are part of either set.

Infinite values come into play in Cantor's work: the cardinality of the natural numbers and the cardinality of the reals are clearly infinite cardinal numbers. But ℵ0, the smallest infinite cardinal, is not a member of either set.

Infinitessimals are fascinating. You can reconstruct differential and integral calculus without using limits by building in terms of infinitessimals. There's some great stuff in surreal numbers playing with infinitessimals. But infinitessimals are not real numbers. You can't reason about them as if they were members of the set of real numbers, because they aren't.

Many of his mistakes are based on this idea.

For example, he's got a very strange idea that infinites and infinitessimals don't have fixed values, but that their values cover a range. The way that he gets to that idea is by asserting the existence
of infinity as a specific, numeric value, and then using it in algebraic manipulations, like taking the "infinityth root" of a real number.

For example, on his way to "proving" that infinitessimals have this range property that he calls "perambulation", he defines a value that he calls κ:

\[ sqrt[infty]{infty} = 1 + kappa\]

In terms of the theory of numbers, this is nonsense. There is no such thing as an infinityth root. You can define an Nth root, where N is a real number, just like you can define an Nth power - exponents and roots are mirror images of the same concept. But roots and exponents aren't defined for infinity, because infinity isn't a number. There is no infinityth root.

You could, if you really wanted to, come up with a definition of exponents that that allowed you to define an infinityth root. But it wouldn't be very interesting. If you followed the usual pattern for these things, it would be a limit: \(sqrt[infty]{x} lim_{nrightarrowinfty} sqrt[n]{x}\). That's clearly 1. Not 1 plus something: just exactly 1.

But Mr. Cringe doesn't let himself be limited by silly notions of consistency. No, he defines things his own way, and runs with it. As a result, he gets a notion that he calls perambulation. How?

Take the definition of κ:

\[ sqrt[infty]{infty} = 1 + kappa\]

Now, you can, obviously, raise both sides to the power of infinity:

\[infty = (1 + kappa)^{infty}\]

Now, you can substitute ℵ0 for \(infty\). (Why? Don't ask why. You just can.) Then you can factor it. His factoring makes no rational sense, so I won't even try to explain it. But he concludes that:

  • Factored and simplified one way, you end up with (κ+1) = 1 + x, where x is some infinitessimal number larger than κ. (Why? Why the heck not?)
  • Factored and simplified another way, you end up with (κ+1) = ℵ
  • If you take the mean of of all of the possible factorings and reductions, you get a third result, that (κ+1) = 2.

He goes on, and on, and on like this. From perambulation to perambulating reciprocals, to subambulation, to ambulation. Then un-ordinals, un-sets... this is really an absolute masterwork of utter insane crackpottery.

Do download it and take a look. It's a masterpiece.

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