Re: atomic

David BL wrote:
...
>
> Here is an example:
>
> Claim: if t1 => t2 & t2 => t3 then t1 => t3
> Proof:
> if a in (attribs(t1) intersect attribs(t3)) then
>
> if a in attribs(t2) then
> a in (attribs(t1) intersect attribs(t2)) so t1(a) is a
> subset of t2(a)
> a in (attribs(t2) intersect attribs(t3)) so t2(a) is a
> subset of t3(a)
> so t1(a) is a subset of t3(a)
> else
> a in (attribs(t1) \ attribs(t2)) so t1(a) = {}
> so t1(a) is a subset of t3(a)
>
> else if a in (attribs(t1) \ attribs(t3)) then
>
> if a in attribs(t2) then
> a in (attribs(t1) intersect attribs(t2)) so t1(a) is a
> subset of t2(a)
> a in (attribs(t2) \ attribs(t3)) so t2(a) = {}
> so t1(a) = {} (because subset of empty set is empty)
> else
> a in (attribs(t1) \ attribs(t2)) so t1(a) = {}
>
>
> I don't know about you but writing out these sorts of proofs is not my
> idea of fun!
>
>
>

Let alone writing them, I find it a struggle to read proofs, which is about all I can do since the average idiot can tear any proof of mine to shreds. But on the odd occasion when I can follow one and it seems right, I always feel the effort was worth it and it makes me very happy. Received on Wed Nov 07 2007 - 04:44:22 CET