2024/09/09 by Towsner, Henry, Walsh, James
#FOS: Mathematics #Logic (math.LO)
paper · doi:10.48550/arxiv.2409.05973
For which choices of X,Y,Z∈\Σ11,Π11\ does no sufficiently strong X-sound and Y-definable extension theory prove its own Z-soundness? We give a complete answer, thereby delimiting the generalizations of Gödel's second incompleteness theorem that hold within second-order arithmetic.