Re: [Haskell-cafe] Is there a name for this property: x + x - x == x

On 06/04/2014 06:34 PM, Omari Norman wrote:

It's not quite idempotence, because more than one function is involved.

It's a common property and I figure I can write a higher order function to build QuickCheck tests for it. I was just wondering if it has a name.

Hello Omari, I guess it's a corollary of two group axioms. There exists an identity element e such what for any a a + e == e + a == a. And for any element a inverse element -a exists, such that a + (-a) == e. Take a look at http://en.wikipedia.org/wiki/Group_%28mathematics%29 Why not compose a name out of these two? :)