53 citations · 246 across the 22 of their papers we have counts for
5 papers · 1 filter
Testing definitional equivalence of theories via automorphism groups
H. Andréka, J. Madarász, I. Németi +1
Two first-order logic theories are definitionally equivalent if and only if there is a bijection between their model classes that preserves isomorphisms and ultraproducts (Theorem…
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…
What properties of numbers are needed to model accelerated observers in relativity?
Gergely Székely
We investigate the possible structures of numbers (as physical quantities) over which accelerated observers can be modeled in special relativity. We present a general axiomatic the…
Vienna Circle and Logical Analysis of Relativity Theory
H. Andréka, J. X. Madarász, I. Németi +2
In this paper we present some of our school's results in the area of building up relativity theory (RT) as a hierarchy of theories in the sense of logic. We use plain first-order l…