We characterize the effective content and the proof-theoretic strength of a Ramsey-type theorem for bi-colorings of so-called exactly large sets. An exactly large set is a set X ⊂ N such that card(X) ...

Have you ever tried to do the brainteaser below, where you have to connect the dots to make the outline of a house in one continuous stroke without going back over your lines? Or perhaps you've ...

Reverse mathematics is a vibrant programme in mathematical logic that investigates the axioms necessary to establish fundamental theorems throughout mathematics. Central to this endeavour are ...

Little progress had been made in solving Ramsey problems since the 1930s. Now, researchers have found the answer to r(4,t), a longstanding Ramsey problem that has perplexed the math world for decades.