Gear300 Messages 1,212 Reaction score 10 Thread starter Nov 17, 2010 #1 Is the following property exclusive to the identity elements: a- = a (inverse of a = a)?
Office_Shredder Staff Emeritus Science Advisor Gold Member Messages 5,706 Reaction score 1,592 Nov 17, 2010 #2 Nope. For example in Z2, the integers mod 2, you have two elements 0 and 1, and 1+1=0, so 1=-1