From: Alexey Tourbin <at@altlinux.ru>
To: ALT Devel discussion list <devel@lists.altlinux.org>
Subject: Re: [devel] [PATCH] apt virtual packages
Date: Sun, 17 Dec 2006 19:41:28 +0300
Message-ID: <20061217164128.GG6148@localhost.localdomain> (raw)
In-Reply-To: <20061217160933.GE6148@localhost.localdomain>
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On Sun, Dec 17, 2006 at 07:09:33PM +0300, Alexey Tourbin wrote:
> Ага, тут похоже должно быть "<=". Дело в том, что всего одной операции
> "<=" достаточно, чтобы логически вывести все остальные операции сравнения.
>
> (==)(a,b) := (a<=b)&&(b<=a)
> (>=)(a,b) := !(b<=a)
> (!=)(a,b) := !(a==b)
> (<)(a,b) := (a<=b)&&(a!=b)
> (>)(a,b) := (a>=b)&&(a!=b)
>
> А в случае с одной только операцией "<" такой ляпоты не получается,
> потому что не удается логически вывести равенство.
Кажется я гоню, причем от безграмотности а не от большого ума. Если
есть отношение "<", то равенство можно доопределить через отрицание:
(a==b) := !((a<b)||(b<a))
Проверка
(1==1) == !((1<1)||(1<1)) == !(FALSE||FALSE) = !FALSE = TRUE
(1==2) == !((1<2)||(2<1)) == !(TRUE||FALSE) = !TRUE = FALSE
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next prev parent reply other threads:[~2006-12-17 16:41 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-09 22:32 [devel] " Alexey Tourbin
2006-10-09 22:41 ` Dmitry V. Levin
2006-10-10 0:40 ` Alexey Tourbin
2006-10-10 15:39 ` Dmitry V. Levin
2006-10-10 15:52 ` Alexey Tourbin
2006-10-10 22:11 ` Dmitry V. Levin
2006-10-11 0:16 ` Alexey Tourbin
2006-10-12 9:18 ` Serge Pavlovsky
2006-12-07 22:52 ` Dmitry V. Levin
2006-12-08 21:27 ` Alexey Tourbin
2006-12-08 21:43 ` Dmitry V. Levin
2006-12-08 21:59 ` Alexey Tourbin
2006-12-08 22:01 ` Dmitry V. Levin
2006-12-08 22:23 ` Dmitry V. Levin
2006-12-13 3:35 ` Alexey Tourbin
2006-12-14 23:40 ` Alexey Tourbin
2006-12-14 23:46 ` Alexey Tourbin
2006-12-14 23:54 ` Alexey Tourbin
2006-12-15 1:25 ` Alexey Tourbin
2006-12-15 13:49 ` Michael Shigorin
2006-12-15 16:52 ` Alexey Tourbin
2006-12-15 22:27 ` Dmitry V. Levin
2006-12-15 22:42 ` Alexey Tourbin
2006-12-16 12:03 ` Alexey I. Froloff
2006-12-16 20:19 ` Alexey Tourbin
2006-12-16 21:02 ` Dmitry V. Levin
2006-12-16 21:08 ` Alexey Tourbin
2006-12-16 21:26 ` Dmitry V. Levin
2006-12-16 21:42 ` Alexey Tourbin
2006-12-17 13:51 ` Alexey I. Froloff
2006-12-17 14:12 ` Alexey Tourbin
2006-12-17 16:47 ` [devel] Papadimitriou Alexey Tourbin
2006-12-17 16:58 ` [devel] apt virtual packages Alex V. Myltsev
2006-12-17 17:45 ` Alexey Tourbin
2006-12-17 17:57 ` [devel] [JT] " Alex V. Myltsev
2006-12-17 18:13 ` Alexey Tourbin
2006-12-17 9:58 ` [devel] " Alexey Tourbin
2006-12-17 10:02 ` Alexey Tourbin
2006-12-17 10:37 ` Alexey Tourbin
2006-12-17 13:43 ` [devel] [PATCH] " Alexey Tourbin
2006-12-17 13:46 ` [devel] gendiff Alexey Tourbin
2006-12-17 14:14 ` [devel] [PATCH] apt virtual packages Alexey Tourbin
2006-12-17 16:09 ` Alexey Tourbin
2006-12-17 16:15 ` Alexey Tourbin
2006-12-17 17:05 ` Hihin Ruslan
2006-12-17 17:17 ` Alexey Tourbin
2006-12-17 16:41 ` Alexey Tourbin [this message]
2006-12-17 16:49 ` [devel] std::sort Alex V. Myltsev
2006-12-17 17:15 ` Alexey Tourbin
2006-12-17 17:54 ` [devel] [JT] std::sort Alex V. Myltsev
2006-12-17 18:06 ` Alexey Tourbin
2006-12-17 19:42 ` Hihin Ruslan
2006-12-17 20:01 ` Hihin Ruslan
2006-12-17 20:33 ` Hihin Ruslan
2006-12-17 20:18 ` Alex V. Myltsev
2006-12-18 7:51 ` Hihin Ruslan
2006-12-18 10:39 ` [devel] [PATCH] apt virtual packages Led
2006-12-18 13:17 ` Alexey Tourbin
2006-12-17 16:51 ` Dmitry V. Levin
2006-12-20 17:25 ` Alexey Tourbin
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