Timeline for Does this multiplicative function have a name? If so, what is known about it?

9 events

when toggle format	what		by	license	comment
Oct 18, 2018 at 14:45	history	edited	GH from MO		edited tags
Oct 18, 2018 at 14:32	answer	added	AccidentalFourierTransform		timeline score: 8
Oct 18, 2018 at 14:03	comment	added	Martin Sleziak		I am not sure to which extent this is interesting, but here is another context in which this function appears: How can we show the equality $[SL_2(\mathbb Z): \Gamma_0(N)]=N\prod_{p\mid N}\left(1+\frac1p\right)$?. (As you can probably guess, I found the question using Approach0.)
Oct 18, 2018 at 14:01	comment	added	Chris Wuthrich		$\psi(n) = \# \mathbb{P}^1(\mathbb{Z}/n\mathbb{Z})$ is the number of points on the projective line.
Oct 18, 2018 at 13:53	vote	accept	Stanley Yao Xiao
Oct 18, 2018 at 13:50	answer	added	GH from MO		timeline score: 12
Oct 18, 2018 at 13:30	comment	added	Martin Sleziak		I found using Approach0 that this function is mentioned in this post: Mean Value of a Multiplicative Function close to $n$ in Terms of the Zeta Function. The topic of that post is exactly deriving some kind of asymptotic formula for $\sum_{n \leq X} \psi(n)$.
Oct 18, 2018 at 13:28	history	edited	Martin Sleziak		added a top-level tag; https://meta.mathoverflow.net/questions/1457/why-are-mo-tags-formatted-as-they-are
Oct 18, 2018 at 13:26	history	asked	Stanley Yao Xiao	CC BY-SA 4.0