{"schema":"vela.problem-packet.v0.1","problem":723,"statement":"If there is a finite projective plane of order $n$ then must $n$ be a prime power?A finite projective plane of order $n$ is a collection of subsets of $\\{1,\\ldots,n^2+n+1\\}$ of size $n+1$ such that every pair of elements is contained in exactly one set.","status":"open","seam":"raw","closureRoutes":[],"obligations":[],"attestations":[],"attempts":[],"velaLean":[],"oeis":[],"generated_note":"derived view; the signed event log is the source of truth (vela check / vela reproduce)"}