2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/67783We describe for any Riemannian manifold a certain infinitesimal neighbourhood of the diagonal. Semi-conformal maps are analyzed as those that preserve such neighbourhoods; harmonic maps are analyzed as those that preserve mirror image formation for pairs of points in such neighbourhoods.20 pagesDifferential GeometryCategory Theory51K10; 53A30, 53C43text