Skip to main content
17 events
when toggle format what by license comment
Jan 16, 2016 at 3:10 answer added Nik Weaver timeline score: 2
Jan 15, 2016 at 5:43 history edited Lao-tzu CC BY-SA 3.0
added 5 characters in body
Jan 14, 2016 at 16:25 comment added Qiaochu Yuan @Lao-tzu: by $A^{\vee}$ i mean the Pontryagin dual of $A$. By $\widehat{\mathbb{Z}}$ I mean the profinite integers.
Jan 14, 2016 at 15:27 comment added Yemon Choi @Dirk But I think the question is hoping to see the continuous FT as a limit of the discrete one, and I think that perspective while obviously attractive can be misleading if applied without caution
Jan 14, 2016 at 15:23 comment added Yemon Choi The Bohr compactification of ${\mathbb R}$ looks nothing like a torus...
Jan 14, 2016 at 11:31 comment added Dirk Interpreting Fourier inversion as a limit is not only interpreting but is the right way to see Fourier inversion in $L^2$. One defines the Fourier transform by extending it from Schwartz space (or $L^1\cap L^2$) to $L^2$ and similar for the inverse. To be concrete one can use the limit $\lim_{T\to\infty} \int_{-T}^T \hat f(\xi) \exp(i x\xi) d\xi$…
Jan 14, 2016 at 9:31 history edited Lao-tzu CC BY-SA 3.0
added 119 characters in body
Jan 14, 2016 at 8:14 history edited Lao-tzu CC BY-SA 3.0
added 3 characters in body
Jan 14, 2016 at 8:06 history edited Lao-tzu CC BY-SA 3.0
added 60 characters in body
Jan 14, 2016 at 7:57 answer added Watson Ladd timeline score: -1
Jan 14, 2016 at 7:03 history edited Lao-tzu CC BY-SA 3.0
added 58 characters in body; edited tags
Jan 14, 2016 at 6:42 comment added Lao-tzu What do you mean by $\mathbb{Z}^ˆ∨$?
Jan 14, 2016 at 6:33 history edited მამუკა ჯიბლაძე CC BY-SA 3.0
"series" and "transform" had to change places
Jan 14, 2016 at 6:31 history edited Lao-tzu CC BY-SA 3.0
deleted 5 characters in body
Jan 14, 2016 at 6:24 history edited Lao-tzu CC BY-SA 3.0
added 297 characters in body
Jan 14, 2016 at 6:23 comment added Qiaochu Yuan A simpler and related question is to interpret the "limit" of the Pontryagin duality relationships $\mathbb{Z}_n^{\vee} \cong \mathbb{Z}_n$ as the Pontryagin duality relationship $\mathbb{Z}^{\vee} \cong S^1$. The closest I know how to get is to take categorical limits / colimits, which gets you the duality $\widehat{\mathbb{Z}}^{\vee} \cong \mathbb{Q}/\mathbb{Z}$.
Jan 14, 2016 at 6:15 history asked Lao-tzu CC BY-SA 3.0