The oddity explained.

I've continued to get odd emails from sybil.cumae. I've worked out where the name comes from (By the power of google!!). It seems that there was a mythical oracle called the Cumaean sibyl, about whom there are various legends. I guess this is a sidelong claim that the content of the emails is true. This isn't my only discovery, though. In fact, I now reckon I know what's going on, as I'll explain in a minute.

Although the emails are starting to get a little longer, they are still terse by comparison with other emails. I've started to enjoy getting them; it's fun to check the random odd facts, which are beginning to be a little more interesting, and introduce me to areas I wasn't aware of. A disproportionate number deal with mathematical facts, though, and I think I've finally found one email which is in error:

Date: Tue, 28 Oct 2008 09:59:25 +0000
From: sybil.cumae@googlemail.com
To: sfwc@hotmail.com
Subject: I thought you might want to know...

Any even integer greater than 2 is a sum of two primes.

This is, of course, the Goldbach conjecture. The reason it is called a conjecture is that, although it is widely believed to be true, nobody knows of any way to prove it. I guess whoever is researching the facts in the emails didn't do their homework properly.

However, the content of the email that has finally cleared up this whole mess was as follows:

The winning numbers in the UK national lottery lotto game on Saturday 1st November 2008 will be 18, 19, 25, 30, 33 and 43.

Of course, there is only one way to reliably predict such things in advance: The emails I've been getting are part of an elaborate 'football picks' scam. The way that this usually works is that letters or emails are sent out to (initially huge numbers of) victims with betting tips about who will win particular football matches. For each match, about half of the victims are told that each team will win. Of course, this means that a lot of incorrect predictions are made. Any victim to whom an incorrect prediction has been sent will be abandoned. Eventually, there will be a very small number of victims left, for each of whom all of the predictions so far have been correct.

All that any of these victims are aware of is the sequence of correct predictions which has been sent to them. So they think that the tipsters are giving sound advice. Playing on this mistake, the tipster contacts these victims offering to give further tips in return for a fee, now that their expertise has been 'demonstrated'. The victims pay the fee hoping to win their money back by gambling on the basis of the tips they are given. The tipster, no longer caring whether the victims win or lose, disappears with the fee. Something of this kind was the basis for Derren Brown's 'the System'.

This scam has now become rather well known, (even referenced in 'the Simpsons'), so that running it in this iterative way has become impractical. Accordingly, the scammers who are sending me these emails have modified it to make it less recognisable in at least three ways:

• Numerous other, easy to obtain, facts are also sent. This encourages the user (me) to check those facts, and to imagine that that whoever is sending them has researched all of them. This subtly hides the fact that the final 'fact' is not researched at all.
• All the eggs are put in one basket: Only one prediction (of lottery results) is made, but the prediction is improbable enough to be highly convincing. This removes the repeated predictions which are a giveaway for the usual scam.
• I'm not completely certain about this last point, but it is rather likely. The chances of winning the lottery are about 1 in 14 million, and there are only 60 million people in the UK, so normally to pull this off the scammers would have to email about one person in four. Nobody I've spoken to is getting similar emails, so I think it is very unlikely that they have done so. Instead, my guess is that they have covered the numbers they didn't send by placing a bet on the results of this weeks lottery draw betting that none of their predictions were right.

I've worked out the numbers for this last point and I reckon it could be done. For example, they may have placed a bet of £100,000 that none of the numbers will be 25, thus reducing the number of people they must email to about 1.7 million, which is a much more manageable number (I'd guess about double this number were emailed to give the system some slack). If none of the numbers are 25, then they win their bet and so make a profit of about £14,000. Otherwise, they have lost £100,000 which they must recoup from somebody they have emailed. But one or two of the victims believe that they can predict lottery numbers (and may even have won) and will now be squeezed in the hopes of recouping the lost £100,000 together with a large profit. The money involved here is not precise: It can be scaled up or down depending on the resources available to the scammers and how much they think they can practically squeeze out of the victims.

Needless to say, I haven't bought a ticket.