Re: Little clue

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 11:49 PM 2001-09-07, Pierangelo Masarati wrote:
>> 
>> 
>> --On Donnerstag, 6. September 2001 18:58 +0200 Pierangelo Masarati 
>> <masarati@aero.polimi.it> wrote:
>> 
>> > Look at these two filters:
>> >
>> > '(&(description=xxxx)(ntaccount=*)(mail=*)(!(mysoc=*))(!(mymail=*)))'
>> >
>> > '(&(!(|(mymail=*)(mysoc=*)))(description=xxxx)(ntaccount=*)(mail=*))'
>> 
>> In Boolean algebra these seem to be the same:
>> a ^ b ^ c ^ (!d) ^ (!e)
>> <=> a ^ b ^ c ^ ((!d) ^ (!e)) #assiociativ
>> <=> a ^ b ^ c ^ (!(d v e)) #deMorgan
>> <=> (!(d v e)) ^ a ^ b ^ c #kommutativ
>
>I guess this is the right answer (not only because that's what I expected :)
>
>> However, LDAP uses a 3-state logic. Any terms that evaluate to undef?
>
>I expect them to behave the same also in case the 'mysoc' and 'mymail'
>terms are undef, because of the negations (!), right?

Yes, because !undef is undef  and (&(undef)...) is undef