ITERATING THE COFINALITY- CONSTRUCTIBLE MODEL

Cofinality of the Nonstationary Ideal

We show that the reduced cofinality of the nonstationary ideal NSκ on a regular uncountable cardinal κ may be less than its cofinality, where the reduced cofinality of NSκ is the least cardinality of any family F of nonstationary subsets of κ such that every nonstationary subset of κ can be covered by less than κ many members of F . For this we investigate connections of the various cofinalitie...

Iterating Octagons

In this paper we prove that the transitive closure of a nondeterministic octagonal relation using integer counters can be expressed in Presburger arithmetic. The direct consequence of this fact is that the reachability problem is decidable for flat counter automata with octagonal transition relations. This result improves the previous results of Comon and Jurski [7] and Bozga, Iosif and Lakhnec...

The Cofinality of The Random Graph

We show that under Martin’s Axiom, the cofinality cf(Aut(Γ)) of the automorphism group of the random graph Γ is 2ω.

Iterating Transducers

Iterating Definiteness

A central concept in the study of vagueness is the concept of a borderline case. This concept has its most basic application when we are faced with a question of the form ‘Is x F?’, but are unwilling to answer ‘Yes’ or ‘No’ for a certain distinctive kind of reason. Wanting to be co-operative, we need to say something; by saying ‘It’s a borderline case’, we excuse our failure to give a straightf...