A. Weiermann

collaborators

3 papers

math.LO2026

Goodstein at the Second Threshold: An Independence Result for $I D_{2}$

Oriola Gjetaj, Andreas Weiermann

The classical Goodstein process, defined via hereditary base- $k$ exponential normal form, is a well-known example of a principle unprovable in Peano Arithmetic. In this paper, we g…

math.LO2026

Proof-Theoretic Relations between Higman's and Kruskal's theorem, and Independence Results for Tree-like Structures

Gabriele Buriola, Andreas Weiermann

Higman's lemma and Kruskal's theorem are two of the most celebrated results in the theory of well quasi-orders. In his seminal paper G. Higman obtained what is known as Higman's le…

math.LO2025

Ordinal Analysis of Well-Ordering Principles, Well Quasi-Orders Closure Properties, and $I^£_{n}$ -Collection Schema

Gabriele Buriola, Andreas Weiermann

The study of well quasi-orders, wqo, is a cornerstone of combinatorics and within wqo theory Kruskal's theorem plays a crucial role. Extending previous proof-theoretic results, we…

Goodstein at the Second Threshold: An Independence Result for ID2​

Proof-Theoretic Relations between Higman's and Kruskal's theorem, and Independence Results for Tree-like Structures

Ordinal Analysis of Well-Ordering Principles, Well Quasi-Orders Closure Properties, and I^£n​-Collection Schema

Goodstein at the Second Threshold: An Independence Result for $I D_{2}$

Ordinal Analysis of Well-Ordering Principles, Well Quasi-Orders Closure Properties, and $I^£_{n}$ -Collection Schema