FORCING ISOMORPHISM .2.

Citation
Mc. Laskowski et S. Shelah, FORCING ISOMORPHISM .2., The Journal of symbolic logic, 61(4), 1996, pp. 1305-1320
Citations number
8
Categorie Soggetti
Mathematics, Pure",Mathematics
ISSN journal
00224812
Volume
61
Issue
4
Year of publication
1996
Pages
1305 - 1320
Database
ISI
SICI code
0022-4812(1996)61:4<1305:FI.>2.0.ZU;2-F
Abstract
If T has only countably many complete types, yet has a type of infinit e multiplicity then there is a c.c.c. forcing notion Q such that, in a ny Q-generic extension of the universe, there are non-isomorphic model s M(1) and M(2) of T that can be forced isomorphic by a c.c.c. forcing . We give examples showing that the hypothesis on the number of comple te types is necessary and what happens if 'c.c.c.' is replaced by othe r cardinal-preserving adjectives. We also give an example showing that membership in a pseudo-elementary class can be altered by very simple cardinal-preserving forcings.