# * A Normalizing Intuitionistic Set Theory with Inaccessible Sets *

## by Wojciech Moczydlowski

2006

- Logical Methods in Computer Science Vol 3, 2007 at http://arxiv.org/abs/0707.1981
- unofficial copies [PDF]

**Abstract**

We propose a set theory strong enough to interpret powerful type theories underlying proof assistants such as LEGO and also possibly Coq, which at the same time enables program extraction from its constructive proofs. For this purpose, we axiomatize an impredicative constructive version of Zermelo-Fraenkel set theory IZF with Replacement and

*w*-many inaccessibles, which we call IZFR_R

*w*. Our axiomatization utilizes set terms, an inductive definition of inaccessible sets and the mutually recursive nature of equality and membership relations. It allows us to define a weakly-normalizing typed lambda calculus corresponding to proofs in IZFR_R

*w*according to the Curry-Howard isomorphism principle. We use realizability to prove the normalization theorem, which provides a basis for program extraction capability.

**bibTex ref: Moc06a**

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