## Abstract A survey of the isomorphic submodels of __V__~Ο~, the set of hereditarily finite sets. In the usual language of set theory, __V__~Ο~ has 2^β΅^0 isomorphic submodels. But other setβtheoretic languages give different systems of submodels. For example, the language of adjunction allows only
Complexity of reals in inner models of set theory
β Scribed by Boban Velickovic; W.Hugh Woodin
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 931 KB
- Volume
- 92
- Category
- Article
- ISSN
- 0168-0072
No coin nor oath required. For personal study only.
β¦ Synopsis
We consider the possible complexity of the set of reals belonging to an inner model M of set theory. We show that if this set is analytic then either l-2, M is countable or else all reals are in M. We also show that if an inner model contains a superperfect set of reals as a subset then it contains all reals. On the other hand, it is possible to have an inner model M whose reals are an uncountable F, set and which does not have all reals. A similar construction shows that there can be an inner model M which computes correctly Ni, contains a perfect set of reals as a subset and yet not all reals are in M. These results were motivated by questions of H. Friedman and K. Prikry.
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