New posts in proof-theory

Can Robinson's Q prove Presburger arithmetic consistent?

Main differences and relations between Sequent Calculus and Natural Deduction

Why wouldn't someone accept Gentzen's consistency proof?

Presburger arithmetic

Gödel's way of teaching non-standard models to Takeuti.

Existence Proofs

Who stole the axioms in Natural Deduction?

Books on logic, proof theory and set theory?

List of Mathematical Impossibilities proved using special tools

Unprovable unprovability

Small proof-theoretic ordinals

Is there a consistent arithmetically definable extension of PA that proves its own consistency?

Two theories proving each others' consistency, take 2

Is many sorted logic really a unifying logic?

Why can't reachability be expressed in first order logic?

Is it possible to formalize the relationship between different proofs of the same theorem?

Can one prove that there is only one proof?

Does "=" have to be interpreted as equality?

Gentzen Cut elimination: Why do we have to "go infinite"?

The Power of Lambda Calculi