New posts in proof-theory

Why are $\Delta_1$ sentences of arithmetic called recursive?

Is there a connection between length of sentence and length of proof?

Is a counterexample considered a rigorous proof that a property is not true?

Proof- vs. model-theoretic definitions of extension and of conservative extension

On Pudlak's "Life in an Inconsistent World"

The category of theorems and proofs

Is everything provable as true, false, or undecidable? [duplicate]

Can all math results be formalized and checked by a computer?

How can know if a proof technique can actually prove something? Specifically, induction

Why do statements which appear elementary have complicated proofs?

Minimal difference between classical and intuitionistic sequent calculus

Aren't constructive math proofs more "sound"?

How to find the shortest proof of a provable theorem?

Can every true theorem that has a proof be proven by contradiction?

Calculus of Natural Deduction That Works for Empty Structures

Has a conjecture ever originally been decided by constructing the proof with mathematical logic?

How can we know we're not accidentally talking about non-standard integers?

Are the Gödel's incompleteness theorems valid for both classical and intuitionistic logic?

If it takes infinite steps to prove a statement, is that a valid proof?

Why is Gödel's Second Incompleteness Theorem important?