Re: Appending lists

[Stefan Monnier]

> The example that I found
>
>   A definition is said to be impredicative if it generalizes
>   over a totality to which the entity being defined belongs.
>   [...] A person x is general-like if and only if, for every
>   property P which all great generals have, x too has P. [2]
>
> is also what I would call recursion.

Notice that the above defines `general-like` but the definition does not
mention `general-like`.  So it is not the usual kind of recursion like
the definition of factorial which refers to factorial.

The circularity in the example above comes from the fact that
`general-like` is a property, so `P` can also be the property
`general-like`.


        Stefan