Math signs

1. Mar 21, 2012

Lizwi

$\oplus$ what does this symbol mean. I was confused in special relativity when notes say u' $\oplus$ v $\neq$ u' + v.

2. Mar 21, 2012

tiny-tim

Hi Lizwi!
What is the context?

Sometimes mathematicians run out of symbols, and recycle a symbol they think nobody wants!

My guess is that this is the addition of relative-velocities formula, and that this author is simply using it as a shorthand for that form of addition.

(in other words: it's his symbol for multiplication in the group of relative-velocities)