Notas de Matemática - Nº 259 2007 http://www.saber.ula.ve/handle/123456789/4764 2026-05-01T02:51:10Z 2026-05-01T02:51:10Z Notas de Matemática http://www.saber.ula.ve/handle/123456789/22785 2018-03-14T08:12:00Z 2008-02-29T09:00:00Z Notas de Matemática 2008-02-29T09:00:00Z Properties and relations between visibility and illumination operators. Formica, Alberto Rodríguez, Mabel http://www.saber.ula.ve/handle/123456789/22786 2018-03-14T08:12:01Z 2008-02-18T09:00:00Z Properties and relations between visibility and illumination operators. Formica, Alberto; Rodríguez, Mabel 2008-02-18T09:00:00Z