Mathematics

yep - stuff like boundary behaviour of subharmonic functions - included a lot of old-fashioned topology and measure theory (much of which I have since forgotten!)

BenjaLim

5:22 PM

@OldJohn Now is the time to make the transition to algebra

Let us motivate each other!

Old John

@BenjaLim :)

BenjaLim

How come you always say there is no time ?

Old John

I have lots of hobbies to fill up my retirement, apart from maths

BenjaLim

such as?

Old John

music, photography, gardening, bonsai, languages, holidays, ...

BenjaLim

5:24 PM

such as?

wow @OldJohn

bonsai
?

do they even grow in england?

Old John

used to include chess in the list - but made a decision a few years ago to give it up - and not played since

It is possible to grow bonsai from quite a number of native british trees - and things like Japanese larch love the climate here :)

I have a number of japanese larch trees in pots - and they all survived a winter when the temp went down to about -13 a couple of years ago

Must go - and help my wife

BenjaLim

@OldJohn

Old John

Good luck with Kempf!

BenjaLim

@OldJohn ok. See you soon. You dod have a few hobbies!

Old John

:)

user19161

5:35 PM

I have finally reinstalled Debian and so now my LaTeX display error is fixed. I will also change my username in about three hours.

user19161

Hello @cha, I am not so excited about a new prime being discovered, since there are infinitely many of them as Euclid says.

Charlie

Ok @jas :)

Orange Harvester

@JasonBourne why did you reinstall debian? Or did you install fedora only to try it out?

user19161

Hey @ora I need some help from you, I will send you an email in one minute...

Novice

I am thinking of entering some random and large powers of 2 and subtracting one from that, then doing the prime test in Mathematica. I might just get lucky!

Orange Harvester

5:39 PM

@JasonBourne Okay.

@Novice Been there, done that. In any case, mathematica is not the way for sure! (Hint: C/C++)

Novice

@OrangeHarvester Loops?

Orange Harvester

(Another Hint: GPGPU, CUDA)

Charlie

I would ask one dollar for each algarism of yhe biggest prime number I would find

Orange Harvester

Lucas–Lehmer primality test

In mathematics, the Lucas–Lehmer test (LLT) is a primality test for Mersenne numbers. The test was originally developed by Édouard Lucas in 1856, and subsequently improved by Lucas in 1878 and Derrick Henry Lehmer in the 1930s. The test The Lucas–Lehmer test works as follows. Let Mp = 2p − 1 be the Mersenne number to test with p an odd prime (because p is exponentially smaller than Mp, we can use a simple algorithm like trial division for establishing its primality). Define a sequence {s i } for all i ≥ 0 by : s_i= \begin{cases} 4 & \text{if }i=0;...

user19161

@Novice Well, how long would it take for you to know whether it is prime?

Novice

5:42 PM

@JasonBourne That's a good point. I currently don't have Mathematica installed here so can anybody tell how much time they take to do the primality test of that new prime number?

user19161

@OrangeHarvester Yes, I installed Fedora to try it out, needless to say, it did not go well as you shall see in my email to you.

Charlie

A life

user19161

@Novice If it were so simple, people would have discovered the prime way before you did.

Novice

@JasonBourne Indeed.

user19161

It takes a lot of computational power and time.

Orange Harvester

5:43 PM

@Novice We did the test on a GPGPU with 120+ cores on 32 machines. It generally took the algorithm 7-8 days to work out numbers of starting point of orders where there was hope. (I do not remember the stuff exactly). Our problem domain was to check viability of parallelization of the Lucas Lehmer Test.

Novice

@OrangeHarvester Whew.

user19161

So with 318 answers and 4 questions and an association bonus of 100 and a rep of 16,100, my average vote per post is now exactly 5. Not too bad. I think I should keep my account for now...

Novice

@JasonBourne Why did you delete your ELU account? :-(

user19161

@Novice I wanted to focus solely on math. One day I might delete this too.

Novice

@JasonBourne Oh myyy...

Transcript for

$Mathematics$ Mathematics