New posts in Proof Theory

Interpreting proper elementarily equivalent end extensions?

Status of proof by contradiction and excluded middle throughout the history of mathematics?

How can the simply typed lambda calculus be Turing-incomplete, yet stronger than second-order logic?

"Strange" proofs of existence theorems

What does it mean to suspect that two conjectures are logically equivalent?

cut-elimination provable in PRA

Notable examples of syntactic proofs whose existence is guaranteed by completeness, but having been found later than a semantic proof?

Asymmetric $A \iff B$ proofs

Who first proved that we can prove that we prove things we prove?

What exactly is a judgement?