Ideals on the real line and Ulam's problem
Idéaux et types sur les corps séparablement clos
If it looks and smells like the reals...
Given a topological space ⟨X,T⟩ ∈ M, an elementary submodel of set theory, we define to be X ∩ M with topology generated by U ∩ M:U ∈ T ∩ M. We prove that if is homeomorphic to ℝ, then . The same holds for arbitrary locally compact uncountable separable metric spaces, but is independent of ZFC if “local compactness” is omitted.
In which categories are first-order axiomatizable hulls characterizable by ultraproducts ?
Incompactness in languages with infinitely long expressions
Indécidabilité de la théorie des anneaux de séries formelles à plusieurs indéterminées
Index sets of classes of automatic structures.
Index sets of classes of automatic structures.
Index sets of decidable models.
Indicators, recursive saturation and expandability
Inessential combinations and colorings of models.
Inf-datalog, modal logic and complexities
Inf-Datalog extends the usual least fixpoint semantics of Datalog with greatest fixpoint semantics: we defined inf-Datalog and characterized the expressive power of various fragments of inf-Datalog in [16]. In the present paper, we study the complexity of query evaluation on finite models for (various fragments of) inf-Datalog. We deduce a unified and elementary proof that global model-checking (i.e. computing all nodes satisfying a formula in a given structure) has 1. quadratic data complexity...
Inf-datalog, Modal Logic and Complexities
Inf-Datalog extends the usual least fixpoint semantics of Datalog with greatest fixpoint semantics: we defined inf-Datalog and characterized the expressive power of various fragments of inf-Datalog in [CITE]. In the present paper, we study the complexity of query evaluation on finite models for (various fragments of) inf-Datalog. We deduce a unified and elementary proof that global model-checking (i.e. computing all nodes satisfying a formula in a given structure) has 1. quadratic data complexity...
Infinitary equivalence of abelian groups
Infinitary stationary logic and abelian groups
Infinitary varieties of structures closed under the formation of complex structures
Infinite Forcing for Boolean valued Models
Initial models and Horn clause axiomatizability.
Injectivity in model theory
Integrating observational and computational features in the specification of state-based, dynamical systems
We present an abstract equational framework for the specification of systems having both observational and computational features. Our approach is based on a clear separation between the two categories of features, and uses algebra, respectively coalgebra to formalise them. This yields a coalgebraically-defined notion of observational indistinguishability, as well as an algebraically-defined notion of reachability under computations. The relationship between the computations yielding new system...