2018/10/17 by Roman Kossak, Kossak, Roman, Bartosz Wcisło +1
Computer Science · #03C62 #03H15 #Computability, Logic, AI Algorithms #FOS: Mathematics #Logic (math.LO) #Logic, Reasoning, and Knowledge #Logic, programming, and type systems
paper · pdf · doi:10.48550/arxiv.1810.07437
openalex publication_date 2018/10/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We introduce a tool for analysing models of \textnormalCT-, the compositional truth theory over Peano Arithmetic. We present a new proof of Lachlan's theorem that arithmetical part of models of \textnormalPA are recursively saturated. We use this tool to provide a new proof that all models of \textnormalCT- carry a partial inductive truth predicate. Finally, we construct a partial truth predicate defined for formulae from a nonstandard cut which cannot be extended to a full truth predicate satisfying \textnormalCT-.