1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Every nite domain contains an identity element.

  1. Mar 9, 2012 #1
    1. The problem statement, all variables and given/known data
    I'm trying to write a proof ot demonstrate that every finite domain contains
    an identity element.

    2. Relevant equations

    3. The attempt at a solution
    If I can think of the operation from the ring as a mapping...like x->yx..where y are just values from the domain and then to consider the possibility that for one y from the domain the following happens x=xy then maybe this will work.But not for addition
    How should I think about this problem?
  2. jcsd
  3. Mar 9, 2012 #2
    Oh wait but I can manipulate the numbers as I want...I can write x=y*d and y=y*e(this means that y doesn't have to be from the domain because I haven't proved the identity part) and =>x=y*e*d=>x=e*x=>e is and identity element in the domain.Will this work?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook