Sniffnoy comments on Open Thread: March 2010, part 2 - Less Wrong

4 Post author: RobinZ 11 March 2010 05:25PM

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Comment author: zero_call 14 March 2010 12:27:18AM 1 point [-]

It's a mistake everyone makes every now and then - seeing pi/n and thinking it's 2pi/n.

What? Like who, 6th graders?

Comment author: Sniffnoy 14 March 2010 03:02:44AM *  1 point [-]

No, like anyone who isn't watching out for traps caused by bad notation. It's much easier to copy down numbers than it is to alter them appropriately. If you see "e^(pi * i/3)", what stands out is the 3 in the denominator. Except oops, pi actually only means half a circle, so this is a sixth root of unity, not a third one. Part of why I like to just write zeta_n instead of e^(2pi * i/n). Sure, this can be avoided with a bit of thought, but thought shouldn't be required here; notation that forces you to think about something so trivial, is not good notation.

Comment author: wnoise 14 March 2010 08:28:28AM 0 points [-]

omega_n is the notation I most often run across.

Comment author: Sniffnoy 14 March 2010 08:48:45AM 0 points [-]

Hm, I've generally just seen omega for zeta_3.

Comment author: wnoise 14 March 2010 09:08:10AM 0 points [-]

I've certainly used it for that -- but I pattern it with dropping the subscript n, when it is clear when there is only one particular root of unity we're basing off of. I've never ever seen zeta used.