New posts in proof-theory

Difference between "Show" and "Prove"

Why does proof by elimination work?

Is a proof also "evidence"?

Prove that a construction exists: is this a constructive proof or existential proof?

What does "prove" mean?

Why can't you prove the law of the excluded middle in intuitionistic logic (for layman)?

Was the effective coverage of induction really just natural number?

What exactly is circular reasoning?

How to prove the mathematical induction is true?

Tricks for Constructing Hilbert-Style Proofs

Pairing in Presburger arithmetic

Model of concatenation theory with left-cancellation but no right-cancellation

Why an inconsistent formal system can prove everything?

What is the difference between ⊢ and ⊨?

Under the Curry-Howard correspondence or loosely "proofs-as-programs", do we also have "programs-as-proofs" and what would some arb. program prove?

Axiom Systems and Formal Systems

natural deduction: introduction of universal quantifier and elimination of existential quantifier explained

When are two proofs "the same"?

If all sets were finite, how could the real numbers be defined?

Can proof by contradiction 'fail'?