# Re: NULLs: theoretical problems?

From: V.J. Kumar <vjkmail_at_gmail.com>

Date: Sat, 25 Aug 2007 16:39:07 +0200 (CEST)

Message-ID: <Xns99976C5CFB2D4vdghher_at_194.177.96.26>

> Commutativity and associativity.

Date: Sat, 25 Aug 2007 16:39:07 +0200 (CEST)

Message-ID: <Xns99976C5CFB2D4vdghher_at_194.177.96.26>

> On 25 aug, 02:13, "V.J. Kumar" <vjkm..._at_gmail.com> wrote:

>> Jan Hidders <hidd..._at_gmail.com> wrote >> innews:1187998409.227306.271460_at_e9g2000prf.googlegroups.com: >> >> > On 24 aug, 16:35, "V.J. Kumar" <vjkm..._at_gmail.com> wrote: >> >> You may be right, but then why the formula was not written with >> >> an explicit 'and' ? >> >> > Because it does not satisify all the logical laws of an AND, so to >> > avoid confusion another notation is used. >> >> What logical laws of AND are violated when we interpret >> >> 'def(x):f(x)' as 'def(x) and f(x)' ?

*>*> Commutativity and associativity.

Does not 'f(x) and def(x)' evaluate to the same as 'def(x) and f(x)' would where def(x) is interpreted as a definedness predicate ?

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> -- Jan Hidders

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Received on Sat Aug 25 2007 - 16:39:07 CEST