On Wed, Dec 10, 2003 at 05:35:11PM -0500, Tom Lane wrote:
> Kurt Roeckx <Q@ping.be> writes:
> > On Wed, Dec 10, 2003 at 04:54:54PM -0500, Tom Lane wrote:
> >> (a AND b) OR (a AND c)
> >> expands by repeated application of the distributive law to
> >> (a OR a) AND (a OR c) AND (b OR a) AND (b OR c)
>
> > This is wrong.
>
> I don't think so. The distributive law is
>
> a OR (b AND c) == (a OR b) AND (a OR c)
Oh, I was reading it wrong.
So basicly it makes a + bc = (a+b)*(a+c) = a + ab + ac + bc
And ab + ac = a * (a+b) * (a+c) * (b+c) = ab + abc + ac
(This is so much easier to read then using AND and OR.)
Kurt
