Query: implicit recursion

Date: Wed, 15 Mar 89 09:37:11 -0500

In the note:

>       IMPLICIT RECURSION IN THE POLYMORPHIC LAMBDA CALCULUS
>
>                            Gavin Wraith
>                     Department of Mathematics
>                        University of Sussex
>
>                              13/3/89

weakly initial algebras [weakly final coalgebras] were defined
for type expressions A(X), covariant in X. Are these necessarily
initial [final]? If not, is there a non-trivial sufficient 
condition on models (better, a characterization) for when
these constructions are initial [final]? 

Nax Mendler
Cornell