2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/219502We establish a close connection between the intersection multiplicity of three arithmetic Hirzebruch-Zagier cycles and the Fourier coefficients of the derivative of a certain Siegel-Eisenstein series at its center of symmetry. Our main result proves a conjecture of Kudla and Rapoport.Algebraic Geometry14G35text