Search results for 'William P. Hanf' (try it on Scholar)

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  1. William P. Hanf & Dale Myers (1983). Boolean Sentence Algebras: Isomorphism Constructions. Journal of Symbolic Logic 48 (2):329-338.score: 290.0
    Associated with each first-order theory is a Boolean algebra of sentences and a Boolean space of models. Homomorphisms between the sentence algebras correspond to continuous maps between the model spaces. To what do recursive homomorphisms correspond? We introduce axiomatizable maps as the appropriate dual. For these maps we prove a Cantor-Bernstein theorem. Duality and the Cantor-Bernstein theorem are used to show that the Boolean sentence algebras of any two undecidable languages or of any two functional languages are recursively isomorphic where (...)
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  2. William P. Hanf (1968). Review: Carol R. Karp, Languages with Expressions of Infinite Length. [REVIEW] Journal of Symbolic Logic 33 (3):477-478.score: 290.0
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  3. William Hanf (1974). Nonrecursive Tilings of the Plane. I. Journal of Symbolic Logic 39 (2):283-285.score: 120.0
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  4. William Hanf (1965). Model-Theoretic Methods in the Study of Elementary Logic. In J. W. Addison (ed.), The Theory of Models. Amsterdam, North-Holland Pub. Co.. 132--145.score: 120.0
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  5. William Hanf (1960). Review: Hillary Putnam, R. M. Smullyan, Exact Separation of Recursively Enumerable Sets Within Theories. [REVIEW] Journal of Symbolic Logic 25 (4):362-362.score: 120.0
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  6. William Hanf (1966). Review: Lars Svenonius, A Theorem on Permutations in Models. [REVIEW] Journal of Symbolic Logic 31 (3):505-505.score: 120.0
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  7. William Hanf (1966). Review: Lars Svenonius, Some Problems in Logical Model-Theory. [REVIEW] Journal of Symbolic Logic 31 (3):505-506.score: 120.0
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  8. William Hanf (1971). Review: Michael O. Rabin, Yehoshua Bar-Hillel, A Simple Method for Undecidability Proofs and Some Applications. [REVIEW] Journal of Symbolic Logic 36 (1):150-150.score: 120.0
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  9. William Hanf (1996). Svenonius Lars. A Theorem on Permutations in Models. Theoria (Lund), Vol. 25 (1959), Pp. 173–178. Journal of Symbolic Logic 31 (3):505-505.score: 120.0
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  10. William Hanf (1996). Svenonius Lars. Some Problems in Logical Model-Theory. Library of Theoria, No. IV. Gleerup CWK, Lund, and Ejnar Munksgaard, Copenhagen, 1960, 43 Pp. [REVIEW] Journal of Symbolic Logic 31 (3):505-506.score: 120.0
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  11. Jean A. Larson (1974). Review: W. Hanf, On a Problem of Erdos and Tarski; D. Monk, D. Scott, Additions to Some Results of Erdos and Tarski; A. Hajnal, Remarks on the Theory of W. P. Hanf. [REVIEW] Journal of Symbolic Logic 39 (2):332-332.score: 42.0
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  12. H. Gericke (1959). Review: William Hanf, On Some Fundamental Problems Concerning Isomorphism of Boolean Algebras. [REVIEW] Journal of Symbolic Logic 24 (3):251-251.score: 36.0
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  13. John P. Burgess (1978). On the Hanf Number of Souslin Logic. Journal of Symbolic Logic 43 (3):568-571.score: 15.0
    We show it is consistent with ZFC that the Hanf number of Ellentuck's Souslin logic should be exactly $\beth_{\omega_2}$.
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  14. K. Jon Barwise (1972). The Hanf Number of Second Order Logic. Journal of Symbolic Logic 37 (3):588-594.score: 12.0
    We prove, among other things, that the number mentioned above cannot be shown to exist without using some $\Pi_1(\mathscr{P})$ instance of the axiom of replacement.
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  15. Saharon Shelah (1979). Hanf Number of Omitting Type for Simple First-Order Theories. Journal of Symbolic Logic 44 (3):319-324.score: 12.0
    Let T be a complete countable first-order theory such that every ultrapower of a model of T is saturated. If T has a model omitting a type p in every cardinality $ then T has a model omitting p in every cardinality. There is also a related theorem, and an example showing the $\beth_\omega$ cannot be improved.
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