Diverse Classes
Baldwin, John T.
J. Symbolic Logic, Tome 54 (1989) no. 1, p. 875-893 / Harvested from Project Euclid
Let $\mathbf{I}(\mu,K)$ denote the number of nonisomorphic models of power $\mu$ and $\mathbf{IE}(\mu,K)$ the number of nonmutually embeddable models. We define in this paper the notion of a diverse class and use it to prove a number of results. The major result is Theorem B: For any diverse class $K$ and $\mu$ greater than the cardinality of the language of $K$, $\mathbf{IE}(\mu,K) \geq \min(2^\mu,\beth_2).$ From it we deduce both an old result of Shelah, Theorem C: If $T$ is countable and $\lambda_0 > \aleph_0$ then for every $\mu > \aleph_0,\mathbf{IE}(\mu,T) \geq \min(2^\mu,\beth_2)$, and an extension of that result to uncountable languages, Theorem D: If $|T| < 2^\omega,\lambda_0 > |T|$, and $|D(T)| = |T|$ then for $\mu > |T|$, $\mathbf{IE}(\mu,T) \geq \min(2^\mu,\beth_2).$
Publié le : 1989-09-14
Classification: 
@article{1183743024,
     author = {Baldwin, John T.},
     title = {Diverse Classes},
     journal = {J. Symbolic Logic},
     volume = {54},
     number = {1},
     year = {1989},
     pages = { 875-893},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183743024}
}
Baldwin, John T. Diverse Classes. J. Symbolic Logic, Tome 54 (1989) no. 1, pp.  875-893. http://gdmltest.u-ga.fr/item/1183743024/