4 papers
The semijoin algebra and the guarded fragment
Dirk Leinders, Jerzy Tyszkiewicz, Jan Van den Bussche
The semijoin algebra is the variant of the relational algebra obtained by replacing the join operator by the semijoin operator. We discuss some interesting connections between the…
On the expressive power of semijoin queries
Dirk Leinders, Jerzy Tyszkiewicz, Jan Van den Bussche
The semijoin algebra is the variant of the relational algebra obtained by replacing the join operator by the semijoin operator. We provide an Ehrenfeucht-Fraissé game, characterizi…
Embedding conditional event algebras into temporal calculus of conditionals
Jerzy Tyszkiewicz, Achim Hoffmann, Arthur Ramer
In this paper we prove that all the existing conditional event algebras embed into a three-valued extension of temporal logic of discrete past time, which the authors of this paper…
The temporal calculus of conditional objects and conditional events
Jerzy Tyszkiewicz, Arthur Ramer, Achim Hoffmann
We consider the problem of defining conditional objects (a|b), which would allow one to regard the conditional probability Pr(a|b) as a probability of a well-defined event rather t…