Descente Infinie

A proof is only worth what its checking is worth. In 1995 Andrew Wiles proved Fermat's Last Theorem. In 2026 that proof was written out in full, in a language a machine can check — more than a million named definitions and theorems. Why believe a million lines a machine wrote? Because a kernel checks the term, and the kernel does not know where the term came from. This app ships that kernel. Not a picture of one, not a green checkmark: the checker itself, running in your hand, on a proof exported from the real thing. MAKE THE MOVES Start with something you can hold in your head: n + 0 = n. Tap moves, and the app assembles a real proof term and hands it to the kernel, which accepts it or refuses it. Then try 0 + n = n. The same move is refused — and the reason is not a lesson written into the app, it is how addition is defined. Four rungs, and the last one is proved with the terms you…