From: | Alan McKinnon <alan.mckinnon@×××××.com> | ||
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To: | gentoo-user@l.g.o | ||

Subject: | Re: [gentoo-user] Portage 2.2 |
||

Date: | Wed, 24 Jul 2013 21:16:13 | ||

Message-Id: | 51F04380.1000909@gmail.com |
||

In Reply to: | Re: [gentoo-user] Portage 2.2 by gottlieb@nyu.edu |

1 | On 24/07/2013 22:15, gottlieb@×××.edu wrote: |

2 | > On Wed, Jul 24 2013, Willie WY Wong wrote: |

3 | > |

4 | >> Speaking as a mathematician (and A. Gottlieb will agree with me), I |

5 | >> would be rather annoyed that they chose (if this is not a misquote |

6 | >> from the original proposed documentation) to use '/' for set |

7 | >> difference instead of '\' as it is supposed to be. |

8 | > |

9 | > I was also surprised to see `/'. A part of me was going to send about |

10 | > quotient groups (the normal usage of '/') but I managed to refrain |

11 | > myself. However, now that willie has opened the door ... |

12 | > |

13 | > / is normally used for quotients. For example, if we take the group Z |

14 | > of integers under addition and the subgroup 2Z of the even integers, |

15 | > then Z / 2Z is the quotient that results from taking Z and identifying |

16 | > all the elements of 2Z. So in Z / 2Z, all the even integers are zero |

17 | > and hence all odd integers are equivalent (since they differ by even |

18 | > integers, which are zero). Thus the quotient has only 2 elements and is |

19 | > the familiar group Z2, the integers mod 2. |

20 | > |

21 | > The above can be generalized. |

22 | > |

23 | > allan |

24 | > |

25 | |

26 | In portage's defense, the symbol used is not really mathematical |

27 | notation, it's an operator used in code, and only in code. |

28 | |

29 | We do this lots: |

30 | |

31 | * is multiplication |

32 | ^ is exponentiation |

33 | % is modulus (sometimes just mod) |

34 | |

35 | and several more, all driven by the lack of appropriate symbols on early |

36 | ASCII keyboards (and the majority of current keyboards...) |

37 | |

38 | I would probably have selected "/" as well if I were the implementer, |

39 | but that's because I heavily resist using backslash for anything other |

40 | than escapes. My brain usually will not let me go against this one... |

41 | |

42 | You mathematician chaps could probably resolve this one nicely for |

43 | yourselves by treating it as just another mangle by Applied |

44 | Mathematicians <====== joke :-) |

45 | |

46 | |

47 | -- |

48 | Alan McKinnon |

49 | alan.mckinnon@×××××.com |

Subject | Author |
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Re: [gentoo-user] Portage 2.2 | gottlieb@×××.edu |

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