72 citations · 342 across the 22 of their papers we have counts for
23 papers
Some Unpublished Letters by Gödel and von Neumann in the Fraenkel Archive
Paolo Mancosu, Richard Zach
Several letters by Kurt Gödel and Johann (János) von Neumann from the (so far uncatalogued) archive of Abraham (Adolf) Fraenkel at the National Library of Israel are published and…
An Epimorphism between Fine and Ferguson's Matrices for Angell's AC
Richard Zach
Angell's logic of analytic containment AC has been shown to be characterized by a 9-valued matrix NC by Ferguson, and by a 16-valued matrix by Fine. It is shown that the former is…
The Genealogy of ''
Landon D. C. Elkind, Richard Zach
The use of the symbol for disjunction in formal logic is ubiquitous. Where did it come from? The paper details the evolution of the symbol in its historical and logic…
Cut elimination and normalization for generalized single and multi-conclusion sequent and natural deduction calculi
Richard Zach
Any set of truth-functional connectives has sequent calculus rules that can be generated systematically from the truth tables of the connectives. Such a sequent calculus gives rise…
Effective Finite-Valued Approximations of General Propositional Logics
Matthias Baaz, Richard Zach
Propositional logics in general, considered as a set of sentences, can be undecidable even if they have "nice" representations, e.g., are given by a calculus. Even decidable propos…
Epsilon Theorems in Intermediate Logics
Matthias Baaz, Richard Zach
Any intermediate propositional logic (i.e., a logic including intuitionistic logic and contained in classical logic) can be extended to a calculus with epsilon- and tau-operators a…