I made a joke today that no matter what song I start with on Pandora, I always eventually end up at Tom Sawyer by Rush.
Now I’m reminded of a famous theorem that involves starting with any whole number, performing a couple trivial arithmetic operations, rinse and repeat, and the theorem states that you will always end up at 1 eventually, no matter what number you start with. (Or maybe it was 2.)
Anyway, what’s that thing called?
The Collatz Conjecture, but it’s not a theorem.
Alternatively, Goodstein’s theorem, but that’s not what I imagine you have in mind in saying “trivial arithmetic operations”.
Alternatively, Indistinguishable’s “Keep subtracting 1” theorem.
But, really, the Collatz Conjecture. I’m sure that’s what you’re thinking of.
Yes, Collatz is the one. Thanks!
Since we have an answer already…
Whenever someone presents a “Name that…” question to me…I want to answer “Bob. I’ll name it Bob. Thank’s for asking.”
-D/a
Look out, Fields Medal!
What a coincidence; that’s also the Chronos Lossless Compression Algorithm. It’s not guaranteed to reduce the size of the input, but it will never increase it, and if repeated enough times, it’ll compress any input file enough to fit on a floppy disc.
What do you do if the input file is already 0?
Obligatory XKCD link. xkcd: Collatz Conjecture
I’ve also heard it called by the much more evocative name of “hailstone conjecture”. It goes up and down repeatedly, but eventually falls to earth.
I don’t get the joke. That isn’t true of either of the theorem/conjecture mentioned…
He’s referring to Indistinguishable’s theorum.