Re: contrib/intarray vs empty arrays

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От
Greg Stark
Тема
Re: contrib/intarray vs empty arrays
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4136ffa0904090629o1aa3f5daw435b7ff58df9fea9@mail.gmail.com
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contrib/intarray vs empty arrays Tom Lane <tgl@sss.pgh.pa.us>
Re: contrib/intarray vs empty arrays Teodor Sigaev <teodor@sigaev.ru>
Re: contrib/intarray vs empty arrays Greg Stark <stark@enterprisedb.com>
Re: contrib/intarray vs empty arrays Andrew Gierth <andrew@tao11.riddles.org.uk>
2009/4/9 Teodor Sigaev :
> 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  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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