Talk:Dicyclic group
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Dicylic groups are in general not nilpotent. Consider the case where A is cyclic of order 6. In this case the corresponding dicyclic group of order 12 is not nilpotent. — Preceding unsigned comment added by 141.51.166.3 (talk • contribs) 16:00, 7 July 2003
Is the restriction that n > 1 actually necessary? It seems to me like the dicyclic group of order 4 should simply be the cyclic group. —Caesura(t) 00:09, 24 June 2006 (UTC)
Different definitions
[edit]It appears different authors have different definitions. Some call all of these groups generalized quaternion groups. See my edits there for more info. RobHar (talk) 09:53, 7 July 2009 (UTC)
Connection between generalized quaternion group and dicyclic group
[edit]I think "More generally, when n is a power of 2, the dicyclic group is isomorphic to the generalized quaternion group." is wrong. Because the conditions a^(2n) = 1 (if I interpret a^(2n) = 1 so, that a has order 2n) and b^2 = a^n for dicyclic groups implies order(b) = 4 and so it has the same presentation as sie quaternion group. Where is my mistake? — Preceding unsigned comment added by 141.51.131.52 (talk) 16:01, 9 January 2013 (UTC)
- Hmmmm.. this article isn't well referenced! I have a reference that defines the first part, "When n = 2, the dicyclic group is isomorphic to the quaternion group Q." but not on the second above, with the generalized quaternion group. Okay, Coxeter talks about it at [1] in Regular Complex Polytopes p. 82. But perhaps there are different definitions so maybe someone else can help clarify? Tom Ruen (talk) 23:52, 9 January 2013 (UTC)
Visualising this group
[edit]I've been trying to figure out how to visualise this group for a while. Clearly Dicn is a variation of Dih2n in which x is of order 4 instead of 2. But I think I've finally come up with something. Consider a regular n-gonal prism, and then powers of a are represented by rotations about the prism's central axis, and x by an unusual kind of flip in which the top face and bottom face are rotated about perpendicular axes.
What do you think? Can anyone here do better? — Smjg (talk) 20:06, 2 January 2014 (UTC)
- I'm outside my domain here, but I see the Quaternion group, Q8, is Dic2. And there are Cayley graphs at Quaternion_group#Cayley_graph comparing to Dih2. So that's the best visualization I know. Tom Ruen (talk) 20:35, 2 January 2014 (UTC)
- This page has Cayley graphs for Dic8, Dic12, Dic16, Dic20 [2] It seems like this is a better start. Tom Ruen (talk) 21:14, 2 January 2014 (UTC)
- Oh yes, I'd almost forgotten about Cayley graphs. When they're readable they're a good way to visualise groups. Thank you! One of these days I'll try and get a few of them into this article.
- BTW I've noticed that the source uses different notation from what we have here - there Dic12 means the dicyclic group of order 12, which we write as Dic3.
- This might also be the source we need to extend List of small groups a bit more! — Smjg (talk) 01:05, 3 January 2014 (UTC)