2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/78291The paper studies a general inverse eigenvalue problem which contains as special cases many well studied pole placement and matrix extension problems. It is shown that the studied problem corresponds on the geometric side to a central projection from some projective variety. The degree for this variety is computed in the critical dimension.18 pages, LaTeXOptimization and ControlAlgebraic Geometry93B55;15A18text