29 citations · 45 across the 4 of their papers we have counts for
4 papers
On variable non-dependence of first-order formulas
Koen Lefever, Gergely Székely
In this paper, we introduce a concept of non-dependence of variables in formulas. A formula in first-order logic is non-dependent of a variable if the truth value of this formula d…
Distances between formal theories
Michèle Friend, Mohamed Khaled, Koen Lefever +1
In the literature, there have been several methods and definitions for working out if two theories are "equivalent" (essentially the same) or not. In this article, we do something…
On Generalization of Definitional Equivalence to Languages with Non-Disjoint Signatures
Koen Lefever, Gergely Székely
For simplicity, most of the literature introduces the concept of definitional equivalence only to languages with disjoint signatures. In a recent paper, Barrett and Halvorson intro…
Comparing Classical and Relativistic Kinematics in First-Order Logic
Koen Lefever, Gergely Székely
The aim of this paper is to present a new logic-based understanding of the connection between classical kinematics and relativistic kinematics. We show that the axioms of special r…