[FOM] From the modeCZF

[Arnon Avron]

Thanks to Peter Aczel and Albert Ziegler for their clarifications
concerning the difference in CZF between P(N) and N->{0,1}.

If I may, I would like to ask two *last* questions on the subject;

1) Suppose we define in CZF P(N) to be the range of the function
   \lambda f:N->{0,1} {x\in N| f(x)=1}. What expected properties 
   of the powerset of N will be lost?

2) Can one prove in CZF that there is no surjective function
   from N on N->{0,1}?


Arnon Avron