Re: [gentoo-user] Portage 2.2

[gottlieb@nyu.edu]

On Wed, Jul 24 2013, Willie WY Wong wrote:

> Speaking as a mathematician (and A. Gottlieb will agree with me), I
> would be rather annoyed that they chose (if this is not a misquote 
> from the original proposed documentation) to use '/' for set 
> difference instead of '\' as it is supposed to be. 

I was also surprised to see `/'.  A part of me was going to send about
quotient groups (the normal usage of '/') but I managed to refrain
myself.  However, now that willie has opened the door ...

/ is normally used for quotients.  For example, if we take the group Z
of integers under addition and the subgroup 2Z of the even integers,
then Z / 2Z is the quotient that results from taking Z and identifying
all the elements of 2Z.  So in Z / 2Z, all the even integers are zero
and hence all odd integers are equivalent (since they differ by even
integers, which are zero).  Thus the quotient has only 2 elements and is
the familiar group Z2, the integers mod 2.

The above can be generalized.

allan