Sunday, 30 November 2014

elementary number theory - Notation for "the highest power of p that divides n"




If p is a prime and n an integer, is there a standard or commonly used notation for "the highest power of p that divides n"?



It's a concept that is often used repeatedly in number-theoretic proofs (see for example this answer), and a convenient notation could make such proofs much more concise. This answer uses the notation {n,p}, which is convenient but seems not to be widely used.



Edit: Prompted by Thomas Kildetoft's comment below, by a convenient notation I mean one which facilitates not only simple statements such as:




  • m is the highest power of p that divides n.




but also more complex statements such as:




  • m = (The highest power of p that divides n) + 1


Answer



Yes, there is a standard notation, namely pe∣∣n, which says that e is the largest power of p which divides n.



Reference: Martin Aigner, Number Theory.




Edit: For more advanced purposes, like p-adic numbers etc., a common notation is also νp(n), which also then appears in more elementary context. For elementary number theory I have seen pe∣∣n more often, though.


No comments:

Post a Comment

real analysis - How to find limhrightarrow0fracsin(ha)h

How to find lim without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...