Gödel-Dummett and $\mathsf{BD_2}$: Linearity and Depth-Two Branching in Kripke Semantics
Abstract
We study the semantic relationship between Gödel-Dummett logic $\mathsf{GL}$ and bounded-depth-2 logic $\mathsf{BD_2}$, two well-known intermediate logics. While $\mathsf{GL}$ imposes linearity on Kripke frames, $\mathsf{BD_2}$ bounds their depth to two. We prove these logics are incomparable (neither contains the other) through minimal frame conditions. Notably, their combination $\mathsf{GL+BD_2}$ collapses to the logic of one or two world frames, bringing it remarkably close to classical logic. This illustrates how controlling breadth and depth in intuitionistic semantics leads to mutually exclusive structural constraints. Finally, we give a conceptual and philosophical interpretation of the previous results. This is an extended abstract of work in progress. Comments and suggestions welcome at: vicent.navarro@ub.edu
Fields of Study & Subjects
Advanced Algebra and Logic
Logic
Reasoning
and Knowledge
Advanced Topology and Set Theory
Publication details
- Journal / source
- arXiv (Cornell University)
- Publication date
- 10 January 2026
- Document type
- Preprint