[Haskell-cafe] Is there a name for this property: x + x - x == x
akamaus at gmail.com
Wed Jun 4 14:45:29 UTC 2014
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.
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? :)
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