ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Sat, 25 Sep 2010 21:09:33 +0200How does sage deal with choosing branches? Examples?https://ask.sagemath.org/question/7710/how-does-sage-deal-with-choosing-branches-examples/[http://en.wikipedia.org/wiki/Principal\_branch][1]
[http://en.wikipedia.org/wiki/Exponentiation#Failure\_of\_power\_and\_logarithm\_identities][2]
[1]: http://en.wikipedia.org/wiki/Principal_branch
[2]: http://en.wikipedia.org/wiki/Exponentiation#Failure_of_power_and_logarithm_identitiesSat, 25 Sep 2010 15:34:50 +0200https://ask.sagemath.org/question/7710/how-does-sage-deal-with-choosing-branches-examples/Answer by kcrisman for <p><a href="http://en.wikipedia.org/wiki/Principal_branch">http://en.wikipedia.org/wiki/Principal_branch</a></p>
<p><a href="http://en.wikipedia.org/wiki/Exponentiation#Failure_of_power_and_logarithm_identities">http://en.wikipedia.org/wiki/Exponentiation#Failure_of_power_and_logarithm_identities</a></p>
https://ask.sagemath.org/question/7710/how-does-sage-deal-with-choosing-branches-examples/?answer=11695#post-id-11695There are lots of ways, but basically it usually makes a choice based on whatever software is involved in the computation. For instance, see the latest Pynac update (#9901) for some information about this where conjugation doesn't commute with a lot of functions on the branch cut line segment.
I don't think there is some coherent underlying philosophy of branch cuts, other than agreeing with other systems when there is such agreement.Sat, 25 Sep 2010 21:09:33 +0200https://ask.sagemath.org/question/7710/how-does-sage-deal-with-choosing-branches-examples/?answer=11695#post-id-11695