categories: Re: Category Theory and Hereditarily-Finite Sets

[Wilkins E B <elwood@essex.ac.uk>]

Paul Taylor wrote:

> > Hereditarily-finite sets are becoming increasingly more popular
> > in computer science research.
>
> Why?  Because some ill-advised first year maths lecturer told you that
> the element relation was the foundation of mathematics, maybe?

Maybe because someone read papers by Friedman (1977) which gave the set
theory B which is [Beeson] "the theory of hereditary extensional sets of
finite rank" and which is strong enough to model Bishop-style constructive
mathematics. This seems to be a good reason.

Elwood

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 Dr Elwood Wilkins          tel:  (+44) (0)1206 872771
 Senior Research Officer    fax: (+44) (0)1206 872788
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