13 found
Order:
  1.  19
    An Interpolation Theorem for First Order Logic with Infinitary Predicates.Tarek Sayed-Ahmed - 2007 - Logic Journal of the IGPL 15 (1):21-32.
    An interpolation Theorem is proved for first order logic with infinitary predicates. Our proof is algebraic via cylindric algebras.1.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   7 citations  
  2.  29
    A Neat Embedding Theorem For Expansions Of Cylindric Algebras.Tarek Sayed-Ahmed & Basim Samir - 2007 - Logic Journal of the IGPL 15 (1):41-51.
    We generalize two classical results on cylindric algebra to certain expansions of cylindric algebras where the extra operations are defined via first order formulas. The first result is the Neat Embedding Theorem of Henkin and the second is Monk's classical non-finitizability result of the class of representable algebras. As a corollary we obtain known classical results of Johnson and Biro published in the Journal of Symbolic logic.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   5 citations  
  3.  42
    Neat embeddings as adjoint situations.Tarek Sayed-Ahmed - 2015 - Synthese 192 (7):1-37.
    Looking at the operation of forming neat $\alpha $ -reducts as a functor, with $\alpha $ an infinite ordinal, we investigate when such a functor obtained by truncating $\omega $ dimensions, has a right adjoint. We show that the neat reduct functor for representable cylindric algebras does not have a right adjoint, while that of polyadic algebras is an equivalence. We relate this categorial result to several amalgamation properties for classes of representable algebras. We show that the variety of cylindric (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   1 citation  
  4.  13
    On Neat Reducts and Amalgamation.Tarek Sayed-Ahmed - 2007 - Logic Journal of the IGPL 15 (1):33-39.
    We present a property of neat reducts commuting with forming subalgebras as a definability condition.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  5. The class of polyadic algebras has the super amalgamation property.Tarek Sayed-Ahmed - 2010 - Mathematical Logic Quarterly 56 (1):103-112.
     
    Export citation  
     
    Bookmark   2 citations  
  6.  13
    Amalgamation Theorems in Algebraic Logic, an overview.Tarek Sayed-Ahmed - 2005 - Logic Journal of the IGPL 13 (3):277-286.
    We review, and in the process unify two techniques , for proving results concerning amalgamation in several classes studied in algebraic logic. The logical counterpart of these results adress interpolation and definability properties in modal and algebraic logic. Presenting them in a functorial context as adjoint situations, we show that both techniques can indeed be seen as instances of the use of the Keisler-Shelah ultrapower Theorem in proving Robinson's Joint Consistency Theorem. Some new results are surveyed. The results of this (...)
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  7. On the complexity of axiomatizations of the class of representable quasi-polyadic equality algebras.Tarek Sayed-Ahmed - 2011 - Mathematical Logic Quarterly 57 (4):384-394.
     
    Export citation  
     
    Bookmark  
  8. The Class Snr (3) CA (k) is Not Closed Under Completions (vol 16, pg 427, 2008).Tarek Sayed-Ahmed & Basim Samir - 2009 - Logic Journal of the Igpl 17 (1):155-155.
     
    Export citation  
     
    Bookmark  
  9. Weakly representable atom structures that are not strongly representable, with an application to first order logic.Tarek Sayed-Ahmed - 2008 - Mathematical Logic Quarterly 54 (3):294-306.
     
    Export citation  
     
    Bookmark   1 citation  
  10.  18
    Independence Results in Algebraic Logic.Tarek Sayed-Ahmed - 2006 - Logic Journal of the IGPL 14 (1):87-96.
    We formulate several statements in Algebraic Logic that turn out to be independent of ZFC. We relate such statements to Martin's axiom, omitting types for variants of first order logic and topological properties of Baire spaces.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  11.  12
    The Class S.Tarek Sayed-Ahmed & Basim Samir - 2008 - Logic Journal of the IGPL 16 (5):427-429.
    Direct download  
     
    Export citation  
     
    Bookmark  
  12.  5
    On complete representations of algebras of logic.Mohamed Khaled & Tarek Sayed-Ahmed - 2009 - Logic Journal of the IGPL 17 (3):267-272.
    We show that there exists an atomic polyadic equality algebra of dimension n that is elementary equivalent to a completely representable algebra, but its diagonal free reduct is not completely representable.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  13. An Omitting Types Theorem for first order logic with infinitary relation symbols.Tarek Sayed-Ahmed & Basim Samir - 2007 - Mathematical Logic Quarterly 53 (6):564-570.
     
    Export citation  
     
    Bookmark