19 found
Sort by:
  1. Zofia Adamowicz, Leszek Aleksander Kolodziejczyk & J. Paris (2012). Truth Definitions Without Exponentiation and the Σ1 Collection Scheme. Journal of Symbolic Logic 77 (2):649.
    Direct download  
     
    My bibliography  
     
    Export citation  
  2. Zofia Adamowicz, Leszek Aleksander Kołodziejczyk & Jeff Paris (2012). Truth Definitions Without Exponentiation and the Σ₁ Collection Scheme. Journal of Symbolic Logic 77 (2):649-655.
    We prove that: • if there is a model of I∆₀ + ¬ exp with cofinal Σ₁-definable elements and a Σ₁ truth definition for Σ₁ sentences, then I∆₀ + ¬ exp +¬BΣ₁ is consistent, • there is a model of I∆₀ Ω₁ + ¬ exp with cofinal Σ₁-definable elements, both a Σ₂ and a ∏₂ truth definition for Σ₁ sentences, and for each n > 2, a Σ n truth definition for Σ n sentences. The latter result is obtained by (...)
    Direct download (4 more)  
     
    My bibliography  
     
    Export citation  
  3. Zofia Adamowicz & Leszek Aleksander Kolodziejczyk (2010). A Note on the E1 Collection Scheme and Fragments of Bounded Arithmetic. Mathematical Logic Quarterly 56 (2):126-130.
    We show that for each n ≥ 1, if T2n does not prove the weak pigeonhole principle for Σbn functions, then the collection scheme B Σ1 is not finitely axiomatizable over T2n. The same result holds with Sn2 in place of T 2n.
    Direct download (5 more)  
     
    My bibliography  
     
    Export citation  
  4. Zofia Adamowicz & Leszek Aleksander Kołodziejczyk (2007). Partial Collapses of the Complexity Hierarchy in Models for Fragments of Bounded Arithmetic. Annals of Pure and Applied Logic 145 (1):91-95.
    For any n, we construct a model of in which each formula is equivalent to an formula.
    Direct download (3 more)  
     
    My bibliography  
     
    Export citation  
  5. Zofia Adamowicz, Sergei Artemov, Damian Niwiński, Ewa Orłowska, Anna Romanowska & Jan Woleński (2004). Editorial. Annals of Pure and Applied Logic 126 (1-3):3-4.
    Direct download (2 more)  
     
    My bibliography  
     
    Export citation  
  6. Martın Abadi, Yoshihiro Abe, Francine F. Abeles, Andrew Aberdein, Vicente Aboites, Nathanael Ackerman, Roger D. Acord, Zofia Adamowicz, John W. Addison Jr & Fritz Aeschbach (2003). Individual Members 2003. Bulletin of Symbolic Logic 9 (4).
    Direct download (2 more)  
     
    My bibliography  
     
    Export citation  
  7. Zofia Adamowicz & Pawe Zbierski (2003). On Complexity Reduction of Σ1 Formulas. Archive for Mathematical Logic 42 (1):45-58.
    No categories
    Direct download (3 more)  
     
    My bibliography  
     
    Export citation  
  8. Zofia Adamowicz & Teresa Bigorajska (2001). Existentially Closed Structures and Gödel's Second Incompleteness Theorem. Journal of Symbolic Logic 66 (1):349-356.
    We prove that any 1-closed (see def 1.1) model of the Π 2 consequences of PA satisfies ¬Cons PA which gives a proof of the second Godel incompleteness theorem without the use of the Godel diagonal lemma. We prove a few other theorems by the same method.
    Direct download (6 more)  
     
    My bibliography  
     
    Export citation  
  9. Zofia Adamowicz & Paweł Zbierski (2001). On Herbrand Consistency in Weak Arithmetic. Archive for Mathematical Logic 40 (6):399-413.
    We prove that the Gödel incompleteness theorem holds for a weak arithmetic T = IΔ0 + Ω2 in the form where Cons H (T) is an arithmetic formula expressing the consistency of T with respect to the Herbrand notion of provability.
    Direct download (4 more)  
     
    My bibliography  
     
    Export citation  
  10. Zofia Adamowicz (1993). A Contribution to the End-Extension Problem and the Π1 Conservativeness Problem. Annals of Pure and Applied Logic 61 (1-2):3-48.
    We formulate a Π1 sentence τ which is a version of the Tableau consistency of GlΔ0. The sentence τ is true and is provable in GlΔ0 + exp. We construct a model M of GlΔ0+Ω1+τ+BGs1 which has no proper end-extension to a model of GlΔ0+Ω1+τ. Also we prove that GlΔ0+Ω1+τ is not Π1 conservative over GlΔ0+τ.
    Direct download (3 more)  
     
    My bibliography  
     
    Export citation  
  11. Zofia Adamowicz (1992). A Sharp Version of the Bounded Matijasevich Conjecture and the End- Extension Problem. Journal of Symbolic Logic 57 (2):597-616.
    Direct download (6 more)  
     
    My bibliography  
     
    Export citation  
  12. Zofia Adamowicz (1991). On Maximal Theories. Journal of Symbolic Logic 56 (3):885-890.
  13. Patrick Farrington, D. S. Scott & Zofia Adamowicz (1989). Hinges and Automorphisms of the Degrees of Non-Constructibility. Journal of Symbolic Logic 54 (3):1109-1111.
    Direct download  
     
    My bibliography  
     
    Export citation  
  14. Zofia Adamowicz & Roman Kossak (1988). A Note on BΣn and an Intermediate Induction Schema. Mathematical Logic Quarterly 34 (3):261-264.
    No categories
    Direct download (3 more)  
     
    My bibliography  
     
    Export citation  
  15. Zofia Adamowicz (1987). Open Induction and the True Theory of Rationals. Journal of Symbolic Logic 52 (3):793-801.
  16. Zofia Adamowicz & Guillermo Morales-Luna (1985). A Recursive Model for Arithmetic with Weak Induction. Journal of Symbolic Logic 50 (1):49-54.
    Direct download (6 more)  
     
    My bibliography  
     
    Export citation  
  17. Zofia Adamowicz (1977). On Finite Lattices of Degrees of Constructibility. Journal of Symbolic Logic 42 (3):349-371.
    Direct download (5 more)  
     
    My bibliography  
     
    Export citation  
  18. Zofia Adamowicz (1976). On Finite Lattices of Degrees of Constructibility of Reals. Journal of Symbolic Logic 41 (2):313-322.
    Direct download (6 more)  
     
    My bibliography  
     
    Export citation  
  19. Zofia Adamowicz (1976). One More Aspect of Forcing and Omitting Types. Journal of Symbolic Logic 41 (1):73-80.
    Direct download (6 more)  
     
    My bibliography  
     
    Export citation