9 found
Sort by:
  1. Fredrik Engström & Juha Kontinen (2013). Characterizing Quantifier Extensions of Dependence Logic. Journal of Symbolic Logic 78 (1):307-316.
    We characterize the expressive power of extensions of Dependence Logic and Independence Logic by monotone generalized quanti ers in terms of quanti er extensions of existential second-order logic.
    Direct download (5 more)  
     
    My bibliography  
     
    Export citation  
  2. Claes Strannegård, Fredrik Engström, Abdul Rahim Nizamani & Lance Rips (2013). Reasoning About Truth in First-Order Logic. Journal of Logic, Language and Information 22 (1):115-137.
    First, we describe a psychological experiment in which the participants were asked to determine whether sentences of first-order logic were true or false in finite graphs. Second, we define two proof systems for reasoning about truth and falsity in first-order logic. These proof systems feature explicit models of cognitive resources such as declarative memory, procedural memory, working memory, and sensory memory. Third, we describe a computer program that is used to find the smallest proofs in the aforementioned proof systems when (...)
    Direct download (7 more)  
     
    My bibliography  
     
    Export citation  
  3. Fredrik Engström (2012). Generalized Quantifiers in Dependence Logic. Journal of Logic, Language and Information 21 (3):299-324.
    We introduce generalized quantifiers, as defined in Tarskian semantics by Mostowski and Lindström, in logics whose semantics is based on teams instead of assignments, e.g., IF-logic and Dependence logic. Both the monotone and the non-monotone case is considered. It is argued that to handle quantifier scope dependencies of generalized quantifiers in a satisfying way the dependence atom in Dependence logic is not well suited and that the multivalued dependence atom is a better choice. This atom is in fact definably equivalent (...)
    Direct download (8 more)  
     
    My bibliography  
     
    Export citation  
  4. Fredrik Engström & Richard W. Kaye (2012). Transplendent Models: Expansions Omitting a Type. Notre Dame Journal of Formal Logic 53 (3):413-428.
    We expand the notion of resplendency to theories of the kind T + p", where T is a fi rst-order theory and p" expresses that the type p is omitted. We investigate two di erent formulations and prove necessary and sucient conditions for countable recursively saturated models of PA. Some of the results in this paper can be found in one of the author's doctoral thesis [3].
    Direct download (5 more)  
     
    My bibliography  
     
    Export citation  
  5. Fredrik Engström (2008). A Note on Standard Systems and Ultrafilters. Journal of Symbolic Logic 73 (3):824-830.
    Let (M, X) ⊨ ACA₀ be such that P X, the collection of all unbounded sets in X, admits a definable complete ultrafilter and let T be a theory extending first order arithmetic coded in X such that M thinks T is consistent. We prove that there is an end-extension N ⊨ T of M such that the subsets of M coded in N are precisely those in X. As a special case we get that any Scott set with a (...)
    Direct download (5 more)  
     
    My bibliography  
     
    Export citation  
  6. Fredrik Engström (2004). Notions of Resplendency for Logics Stronger Than First-Order Logic. Bulletin of Symbolic Logic 11 (2).
    Direct download  
     
    My bibliography  
     
    Export citation  
  7. Fredrik Engström (2003). Omitting Types in Expansions and Related Strong Saturation Properties. Bulletin of Symbolic Logic 10 (2).
    Direct download  
     
    My bibliography  
     
    Export citation