See below. (01)
> PH> We are quantifying over 4-d entities, ie 'slices' of
> > a 'history-worm' ... which I will write by pairing a name
> > with a time-interval, eg [PatH, 1997-2007]. Person, to wit
> > [PatH, (lifetimeOf PatH)]. It is not a Person. So
> >
> > forall x Employee(x) implies Person(x)
> >
> > is false: in fact, this is a counterexample.
> > So Employee is not < Person.
>
> OK. I accept the point that the definition of
> "Employee < Person" is equivalent to
>
> forall x Employee(x) implies Person(x)
>
> in a 3D ontology, but it creates problems in 4D. (02)
I don't see that this creates a problem for 4D - it's simply *wrong* to
say in 4D (as Pat points out) if one takes 'Person' to be the class of
sums of Person_Slice-s. Under 4D, one could truly say: (03)
Employee < Person_Slice (04)
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