KURSCHAK 1981 Problem 1

Prove that $AB + PQ + QR + RP \le AP + AQ + AR + BP + BQ + BR$ where $A, B, P, Q$ and $R$ are any five points in a plane.

Dataset text AI-MO AoPS. Quoted with source.

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.