I will not put the punchline in the title
Apr. 16th, 2019 01:03 amOK, OK, not talking decision theory here, just more funny math stories. :)
So I went to student combinatorics seminar today (yeah, I know, I haven't actually been a student in years). I haven't bothered to go since the school year started what with the combination of A. working for Truffle and B. living up on north campus, but it's not like I have specific hours I have to keep, so I certainly can go if I want to take the time to go down to central campus. I mean, I've bothered to go occasionally for the Tuesday colloquia, and I went to John's math club talk when he was in town last week (unfortunately this ended up being pretty boring[0]) but I hadn't really bothered with my old haunt of student combinatorics.
But today I happened to be in East Hall for coincidental reasons, and the topic sounded interesting, so I showed up. It was... someone... talking about the distribution of cycles in random permutations. Sorry, I forget the name of the speaker! Anyway, at one point he writes down a moment generating function, right? Which for a random variable X, is
E(etX) = E(1) + tE(X) + ½t²E(X²) + ...
You'll notice I wrote E(1) there... that's deliberate, because that's how the speaker wrote it. He wrote this down and asked, what's E(1)? (Just, like, out of trying to hold too many things in his head at once, it seemed.) 1, people responded. And he's like, oh yeah, 1, and writes down 1.
Then Will adds in: "What value would you expect 1 to have?"
-Harry
[0]Background: Math club talks are targeted at undergrads. Sometimes they're very interesting things I hadn't heard about, that happen to be accessible to undergrads! Sometimes, though, they're pretty standard stuff that you're probably familiar with if you're a grad student or have a PhD. John's talk was one of the latter.
So I went to student combinatorics seminar today (yeah, I know, I haven't actually been a student in years). I haven't bothered to go since the school year started what with the combination of A. working for Truffle and B. living up on north campus, but it's not like I have specific hours I have to keep, so I certainly can go if I want to take the time to go down to central campus. I mean, I've bothered to go occasionally for the Tuesday colloquia, and I went to John's math club talk when he was in town last week (unfortunately this ended up being pretty boring[0]) but I hadn't really bothered with my old haunt of student combinatorics.
But today I happened to be in East Hall for coincidental reasons, and the topic sounded interesting, so I showed up. It was... someone... talking about the distribution of cycles in random permutations. Sorry, I forget the name of the speaker! Anyway, at one point he writes down a moment generating function, right? Which for a random variable X, is
E(etX) = E(1) + tE(X) + ½t²E(X²) + ...
You'll notice I wrote E(1) there... that's deliberate, because that's how the speaker wrote it. He wrote this down and asked, what's E(1)? (Just, like, out of trying to hold too many things in his head at once, it seemed.) 1, people responded. And he's like, oh yeah, 1, and writes down 1.
Then Will adds in: "What value would you expect 1 to have?"
-Harry
[0]Background: Math club talks are targeted at undergrads. Sometimes they're very interesting things I hadn't heard about, that happen to be accessible to undergrads! Sometimes, though, they're pretty standard stuff that you're probably familiar with if you're a grad student or have a PhD. John's talk was one of the latter.
