H HeadOnAPike Oct 2009 20 0 May 28, 2010 #1 How would I go about figuring out how many units are in Zeta 230?

P Purslow May 2010 13 1 May 28, 2010 #2 by zeta 230, do you mean the ring of intergers modulo 230? if so, the units are the invertible elements, ie 1, 3, 77, 7 , 33 ......

by zeta 230, do you mean the ring of intergers modulo 230? if so, the units are the invertible elements, ie 1, 3, 77, 7 , 33 ......

Drexel28 MHF Hall of Honor Nov 2009 4,563 1,566 Berkeley, California May 28, 2010 #3 Purslow said: by zeta 230, do you mean the ring of intergers modulo 230? if so, the units are the invertible elements, ie 1, 3, 77, 7 , 33 ...... Click to expand... Why not just say it? In general \(\displaystyle \text{card }(\mathbb{Z}/n\mathbb{Z})^{\times}=\varphi(n)\) where \(\displaystyle \varphi(n)\) is the number of things less than \(\displaystyle n\) which are relatively prime to it.

Purslow said: by zeta 230, do you mean the ring of intergers modulo 230? if so, the units are the invertible elements, ie 1, 3, 77, 7 , 33 ...... Click to expand... Why not just say it? In general \(\displaystyle \text{card }(\mathbb{Z}/n\mathbb{Z})^{\times}=\varphi(n)\) where \(\displaystyle \varphi(n)\) is the number of things less than \(\displaystyle n\) which are relatively prime to it.

H HeadOnAPike Oct 2009 20 0 May 29, 2010 #4 Yes, the ring of integers mod 230. How do I find out the number of units (inverses for the product) without actually going through them all?

Yes, the ring of integers mod 230. How do I find out the number of units (inverses for the product) without actually going through them all?