Re: choice of character for relational division

Marshall wrote:
...
> It certainly looks as if & is overloaded but ... maybe it isn't!
>
> Suppose the relational = operator is closed over relations.
> That is, its result, rather than being some specific boolean
> type, was instead necessarily a relation. Any empty relation
> would be interpreted as false and any nonempty relation
> is true. In this case we don't need any attributes on the
> result, just to know whether it's empty or not. So
>
> true = DEE
> false = DUM
>
> and the various & characters in the above are *all* natural join.
> ...

Why close it over just relations? Eg., why not always produce DEE or DUM?

p Received on Sun Apr 01 2007 - 15:49:54 CDT