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  1. Rosalie Iemhoff, Logic for A.I. - Solutions.
    Axiom 1 of K is the same as Axiom 1 in L, thus we have nothing to prove. Axiom 2 of K is 2(φ → ψ) → (2φ → 2ψ). We give a derivation of this formula in L: (φ → ψ) ∧ φ → ψ 2((φ → ψ) ∧ φ) → 2ψ (the rule from L) 2(φ → ψ) ∧ 2φ → 2ψ (axiom 3 of L and propositional logic) 2(φ → ψ) → (2φ → 2ψ) (propositional logic) Remain (...)
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  2. Rosalie Iemhoff, Modal Logic.
    This text contains some basic facts about modal logic. For motivation, intuition and examples the reader should consult one of the standard textbooks in the field.
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  3. Rosalie Iemhoff (forthcoming). On Rules. Journal of Philosophical Logic:1-15.
    This paper contains a brief overview of the area of admissible rules with an emphasis on results about intermediate and modal propositional logics. No proofs are given but many references to the literature are provided.
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  4. Jeroen P. Goudsmit & Rosalie Iemhoff (2014). On Unification and Admissible Rules in Gabbay–de Jongh Logics. Annals of Pure and Applied Logic 165 (2):652-672.
    In this paper we study the admissible rules of intermediate logics. We establish some general results on extensions of models and sets of formulas. These general results are then employed to provide a basis for the admissible rules of the Gabbay–de Jongh logics and to show that these logics have finitary unification type.
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  5. Rosalie Iemhoff (2010). Kripke Models for Subtheories of CZF. Archive for Mathematical Logic 49 (2):147-167.
    In this paper a method to construct Kripke models for subtheories of constructive set theory is introduced that uses constructions from classical model theory such as constructible sets and generic extensions. Under the main construction all axioms except the collection axioms can be shown to hold in the constructed Kripke model. It is shown that by carefully choosing the classical models various instances of the collection axioms, such as exponentiation, can be forced to hold as well. The paper does not (...)
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  6. Rosalie Iemhoff (2010). The Eskolemization of Universal Quantifiers. Annals of Pure and Applied Logic 162 (3):201-212.
    This paper is a sequel to the papers Baaz and Iemhoff [4] and [6] in which an alternative skolemization method called eskolemization was introduced that, when restricted to strong existential quantifiers, is sound and complete for constructive theories. In this paper we extend the method to universal quantifiers and show that for theories satisfying the witness property it is sound and complete for all formulas. We obtain a Herbrand theorem from this, and apply the method to the intuitionistic theory of (...)
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  7. Rosalie Iemhoff & George Metcalfe (2009). Proof Theory for Admissible Rules. Annals of Pure and Applied Logic 159 (1):171-186.
    Admissible rules of a logic are those rules under which the set of theorems of the logic is closed. In this paper, a Gentzen-style framework is introduced for analytic proof systems that derive admissible rules of non-classical logics. While Gentzen systems for derivability treat sequents as basic objects, for admissibility, the basic objects are sequent rules. Proof systems are defined here for admissible rules of classes of modal logics, including K4, S4, and GL, and also Intuitionistic Logic IPC. With minor (...)
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  8. Matthias Baaz & Rosalie Iemhoff (2008). On Skolemization in Constructive Theories. Journal of Symbolic Logic 73 (3):969-998.
    In this paper a method for the replacement, in formulas, of strong quantifiers by functions is introduced that can be considered as an alternative to Skolemization in the setting of constructive theories. A constructive extension of intuitionistic predicate logic that captures the notions of preorder and existence is introduced and the method, orderization, is shown to be sound and complete with respect to this logic. This implies an analogue of Herbrand's theorem for intuitionistic logic. The orderization method is applied to (...)
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  9. Sergei Artemov & Rosalie Iemhoff (2007). The Basic Intuitionistic Logic of Proofs. Journal of Symbolic Logic 72 (2):439 - 451.
    The language of the basic logic of proofs extends the usual propositional language by forming sentences of the sort x is a proof of F for any sentence F. In this paper a complete axiomatization for the basic logic of proofs in Heyting Arithmetic HA was found.
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  10. Matthias Baaz & Rosalie Iemhoff (2006). Gentzen Calculi for the Existence Predicate. Studia Logica 82 (1):7 - 23.
    We introduce Gentzen calculi for intuitionistic logic extended with an existence predicate. Such a logic was first introduced by Dana Scott, who provided a proof system for it in Hilbert style. We prove that the Gentzen calculus has cut elimination in so far that all cuts can be restricted to very simple ones. Applications of this logic to Skolemization, truth value logics and linear frames are also discussed.
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  11. Matthias Baaz & Rosalie Iemhoff (2006). The Skolemization of Existential Quantifiers in Intuitionistic Logic. Annals of Pure and Applied Logic 142 (1):269-295.
    In this paper an alternative Skolemization method is introduced that, for a large class of formulas, is sound and complete with respect to intuitionistic logic. This class extends the class of formulas for which standard Skolemization is sound and complete and includes all formulas in which all strong quantifiers are existential. The method makes use of an existence predicate first introduced by Dana Scott.
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  12. Rosalie Iemhoff (2006). On the Rules of Intermediate Logics. Archive for Mathematical Logic 45 (5):581-599.
    If the Visser rules are admissible for an intermediate logic, they form a basis for the admissible rules of the logic. How to characterize the admissible rules of intermediate logics for which not all of the Visser rules are admissible is not known. In this paper we give a brief overview of results on admissible rules in the context of intermediate logics. We apply these results to some well-known intermediate logics. We provide natural examples of logics for which the Visser (...)
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  13. Rosalie Iemhoff (2005). Intermediate Logics and Visser's Rules. Notre Dame Journal of Formal Logic 46 (1):65-81.
    Visser's rules form a basis for the admissible rules of . Here we show that this result can be generalized to arbitrary intermediate logics: Visser's rules form a basis for the admissible rules of any intermediate logic for which they are admissible. This implies that if Visser's rules are derivable for then has no nonderivable admissible rules. We also provide a necessary and sufficient condition for the admissibility of Visser's rules. We apply these results to some specific intermediate logics and (...)
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  14. Rosalie Iemhoff, Dick de Jongh & Chunlai Zhou (2005). Properties of Intuitionistic Provability and Preservativity Logics. Logic Journal of the Igpl 13 (6):615-636.
    We study the modal properties of intuitionistic modal logics that belong to the provability logic or the preservativity logic of Heyting Arithmetic. We describe the □-fragment of some preservativity logics and we present fixed point theorems for the logics iL and iPL, and show that they imply the Beth property. These results imply that the fixed point theorem and the Beth property hold for both the provability and preservativity logic of Heyting Arithmetic. We present a frame correspondence result for the (...)
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  15. Rosalie Iemhoff (2003). Preservativity Logic: An Analogue of Interpretability Logic for Constructive Theories. Mathematical Logic Quarterly 49 (3):230-249.
    In this paper we study the modal behavior of Σ-preservativity, an extension of provability which is equivalent to interpretability for classical superarithmetical theories. We explain the connection between the principles of this logic and some well-known properties of HA, like the disjunction property and its admissible rules. We show that the intuitionistic modal logic given by the preservativity principles of HA known so far, is complete with respect to a certain class of frames.
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  16. Rosalie Iemhoff (2002). Submodels of Kripke Models. [REVIEW] Bulletin of Symbolic Logic 8 (3):440-440.
     
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  17. Rosalie Iemhoff (2002). Review: Albert Visser, Submodels of Kripke Models. [REVIEW] Bulletin of Symbolic Logic 8 (3):440-441.
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  18. Rosalie Iemhoff (2001). A(Nother) Characterization of Intuitionistic Propositional Logic. Annals of Pure and Applied Logic 113 (1-3):161-173.
    In Iemhoff we gave a countable basis for the admissible rules of . Here, we show that there is no proper superintuitionistic logic with the disjunction property for which all rules in are admissible. This shows that, relative to the disjunction property, is maximal with respect to its set of admissible rules. This characterization of is optimal in the sense that no finite subset of suffices. In fact, it is shown that for any finite subset X of , for one (...)
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  19. Rosalie Iemhoff (2001). On the Admissible Rules of Intuitionistic Propositional Logic. Journal of Symbolic Logic 66 (1):281-294.
    We present a basis for the admissible rules of intuitionistic propositional logic. Thereby a conjecture by de Jongh and Visser is proved. We also present a proof system for the admissible rules, and give semantic criteria for admissibility.
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