Un espacio proyectivo S puede ser definido abstractamente como un conjunto P (el conjunto de puntos), junto con el conjunto L de subconjuntos de P (el conjunto de rectas), que satisfacen los siguientes axiomas : Dos puntos distintos p y q están exactamente en una recta.
With the exception of vaccinations, treatments for parasites and compulsory eradication schemes where an animal or group of animals receive more than three courses of treatments with chemically-synthesised allopathic veterinary medicinal products or antibiotics within # months, or more than one course of treatment if their productive lifecycle is less than one year, the livestock concerned, or produce derived from them, may not be sold as organic products, and the livestock shall undergo the conversion periods laid down in ArticleWikiMatrix WikiMatrix