Re: contrib/intarray vs empty arrays - Mailing list pgsql-hackers

From Greg Stark
Subject Re: contrib/intarray vs empty arrays
Date
Msg-id 4136ffa0904090629o1aa3f5daw435b7ff58df9fea9@mail.gmail.com
Whole thread Raw
In response to Re: contrib/intarray vs empty arrays  (Teodor Sigaev <teodor@sigaev.ru>)
List pgsql-hackers
2009/4/9 Teodor Sigaev <teodor@sigaev.ru>:
> contains - all elements of second array are contained in the first one.
> Empty array has no element, so it can't be contained.

That sounds wrong. A <contains> B should surely always be true if B is
empty. ie "for all x, x in B implies x in A". Or put another way,
"contains" just means "is a superset of" and all sets are supersets of
the empty set (even the empty set).

-- 
greg


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