[FOM] Is ZF interpretable in ZF minus extensionality plus X inaccessibles?

Frode Bjørdal frode.bjordal at ifikk.uio.no
Tue Nov 22 16:08:42 EST 2011

As I understand it ZF is not interpretable in ZF minus extensionality;
a reference here is Scott, D., "More on the Axiom of Extensionality,"
pp. 115-131 in Essays on the Foundations of Mathematics, edited by Y.
Bar-Hillel, et al., Hebrew University, Jerusalem, 1966.

Does someone know if ZF is interpretable in ZF minus extensionality
plus some amount of inaccessibles? If it is, what is the lowest amount

Frode Bjørdal
Professor i filosofi
IFIKK, Universitetet i Oslo

More information about the FOM mailing list