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Re: [PATCH] Postinstall script ordering in setup - take 3


On Mon, 2003-03-17 at 07:13, Igor Pechtchanski wrote:

> > And for clarity: my suggested tweak is also not sufficient to provide a
> > weak ordering.
> > Rob
> 
> Rob,
> 
> Your suggested tweak provides a total ordering.  The "unordered(x,y)"
> [!(x < y) && !(y < x)] relation is false for any x != y [since either
> (x < y) or (y < x) always holds].

For my example, yes. The problem is when you introduce z.

>   So all equivalence classes have one
> element: "unordered(x,x)" is always true.  You get transitivity trivially,
> as "unordered(x,y) && unordered(y,z)" is only true if x == y == z, and
> then you also have "unordered(x,z)".

But: we break the ordering transitivity.
> Transitivity
> x < y and y < z implies x < z [3]

y:= foo: gam
x:= gam
z:= bar: foo

both our operators give
x < y && y < z && !x < z
(dep)    (dep)    (alpha)

which isn't transitive.

Rob

-- 
GPG key available at: <http://users.bigpond.net.au/robertc/keys.txt>.

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