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Timeline for Units in quaternionic algebras

Current License: CC BY-SA 3.0

11 events
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May 30, 2022 at 10:59 comment added William of Baskerville And one more question. Can one find an explicit formula for a non-zero group homomorphism $H\to\mathbb Z$?
May 30, 2022 at 8:49 comment added William of Baskerville This is a very nice topic. I was wondering about the statement on the abelianization of $H\subseteq SL(2,\mathbb R)$ being $\mathbb Z^{2g}$. If $H$ acts freely on the hyperbolic plane then I can see an argument involving universal cover. Do you know an explicit reference for the general case?
Apr 23, 2011 at 19:08 comment added akula @David Loeffler: Could you expand a bit on your "favourite case"? Does this description give the rank of the abelianization of the unit group in this case?
Apr 19, 2011 at 23:45 vote accept akula
Apr 14, 2011 at 7:45 history edited David Loeffler CC BY-SA 3.0
corrected an error pointed out by David Speyer; added 3 characters in body
Apr 14, 2011 at 7:45 comment added David Loeffler @akula: I've added some remarks on S-units. @David Speyer: Yes, I am sure you are right.
Apr 14, 2011 at 7:39 history edited David Loeffler CC BY-SA 3.0
typo
Apr 13, 2011 at 17:29 comment added David E Speyer Should it be twice the genus? I'm not sure, but that seems right to me, since the abelianization of $\pi_1$ of a genus $g$ curve has rank $2g$.
Apr 13, 2011 at 14:28 comment added akula @David Loeffler: Thanks. The finiteness of the unit group in the definite case must be easy -- following just by looking at the norm form. Your explanation of the the indefinite easy really explains what is going on. Do you have anything to add about S-units?
Apr 13, 2011 at 7:34 history edited David Loeffler CC BY-SA 3.0
corrected typo
Apr 13, 2011 at 7:27 history answered David Loeffler CC BY-SA 3.0