Re: NULLs: theoretical problems?
From: V.J. Kumar <vjkmail_at_gmail.com>
Date: Sat, 11 Aug 2007 02:52:18 +0200 (CEST)
Message-ID: <Xns9988D452318DBvdghher_at_194.177.96.26>
>
>
> Good catch. It seems that logical implication is not well defined for
> three-value logic.
Date: Sat, 11 Aug 2007 02:52:18 +0200 (CEST)
Message-ID: <Xns9988D452318DBvdghher_at_194.177.96.26>
"David Portas" <REMOVE_BEFORE_REPLYING_dportas_at_acm.org> wrote in news:NM-dncYFOuhqBybb4p2dnAA_at_giganews.com:
> "paul c" <toledobythesea_at_oohay.ac> wrote in message
> news:JXLui.45171$rX4.26997_at_pd7urf2no...
>>
>> (even though I'm not sure in "s{X} = t{X} implies s{Y} = t{Y}"
>> whether "implies" stands for logical implication.)
>>
>
>
> Good catch. It seems that logical implication is not well defined for
> three-value logic.
It is not that three-valued implication is not 'well defined' whatever it means. As a matter of fact, there are a few competing definitions to choose from, Lukaciewicz's, Kleene's and someone else's whose name I do not recall. They define implication in the usual way, with the truth table. Funny, how the subject of nulls and 3VL keeps popping up followed by the usual boring and meaningless discussion ! Received on Sat Aug 11 2007 - 02:52:18 CEST