Determinacy and the Sharp Function on Objects of Type k
Dubose, Derrick Albert
J. Symbolic Logic, Tome 60 (1995) no. 1, p. 1025-1053 / Harvested from Project Euclid
We characterize, in terms of determinacy, the existence of the least inner model of "every object of type $k$ has a sharp." For $k \in \omega$, we define two classes of sets, $(\Pi^0_k)^\ast$ and $(\Pi^0_k)^\ast_+$, which lie strictly between $\bigcup_{\beta < \omega^2} (\beta-\Pi^1_1)$ and $\Delta(\omega^2-\Pi^1_1)$. Let $\sharp_k$ be the (partial) sharp function on objects of type $k$. We show that the determinancy of $(\Pi^0_k)^\ast$ follows from $L \lbrack\ sharp_k \rbrack \models "\text{every object of type} k \text{has a sharp},$ and we show that the existence of indiscernibles for $L\lbrack \sharp_k \rbrack$ is equivalent to a slightly stronger determinacy hypothesis, the determinacy of $(\Pi^0_k)^\ast_+$.
Publié le : 1995-12-14
Classification: 
@article{1183744862,
     author = {Dubose, Derrick Albert},
     title = {Determinacy and the Sharp Function on Objects of Type k},
     journal = {J. Symbolic Logic},
     volume = {60},
     number = {1},
     year = {1995},
     pages = { 1025-1053},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183744862}
}
Dubose, Derrick Albert. Determinacy and the Sharp Function on Objects of Type k. J. Symbolic Logic, Tome 60 (1995) no. 1, pp.  1025-1053. http://gdmltest.u-ga.fr/item/1183744862/