3 articles
General
Goodstein's theorem
Goodstein's theorem is a statement in number theory, proved by Reuben Goodstein in 1944, that every Goodstein sequence eventually reaches 0 but cannot be proved in Peano Arithmetic.
General
Hydra game
The hydra game is a mathematical process, introduced by Laurie Kirby and Jeff Paris in 1982, in which a player cuts heads from a regrowing tree and always wins.
General
Paris–Harrington theorem
The Paris–Harrington theorem, proved by Jeff Paris and Leo Harrington in 1977, strengthens the finite Ramsey theorem and is true but unprovable in Peano Arithmetic.