2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/191519We discuss the Kaluza-Klein reduction of spaces with (anti-)self-dual Weyl tensor and point out the emergence of the Einstein-Weyl equations for the reduction from four to three dimensions. As a byproduct we get a simple expression for the gravitational instanton density in terms of the Kaluza-Klein functions.11 pages, v2: updated Refs., minor changesMathematical PhysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext