🚀 go-pugleaf

In a previous article, fulk@cs.rochester.edu (Mark Fulk) says:

>In article <1992Sep29.161016.19533@ghost.dsi.unimi.it> chinnici@ghost.dsi.unimi.it (roberto riccard chinnici) writes:
>>A question for Recursion Theorists.
>>
>>If you take a partial recursive function phi and two sets I and J such that
>> dom(phi) contains I and range(phi) is included in J, you can define an
>> obvious set-theoretic function f:I->J.
>>
>>The question is: does EVERY surjective f admit a section, i.e. a g:J->I
>> obtained in the same way from a partial recursive function, say psi, such
>> that
>>	for each j in J    f(g(j))=j       ?
>>
>
>Thanks for the nice problem.  If I is recursively enumerable, there is
>such a section.  In general, there is not, 

	Well, I walked right into that one (with my alleged algorithm
for findng the section, which began by sneaking in an enumeration 
of I).

Colin McLarty