BACKGROUND Abū Bakr Muhammad ibn Zakariyyā al-Rāzī, known as Rhazes in the Western world (854-925 CE), was an Iranian polymath, physician and one of the most prominent sages in the medieval period. He wrote several medical books and treaties such as "Continents", a comprehensive medical encyclopedia, treaties in smallpox and measles, "Al-Mansuri" and many other important manuscripts in the medi...

Centers of Arabic culture and literature the Middle Ages were established in Spain. This is related to Arab expansion Iberian Peninsula, which lasted for almost eight centuries. During this time, Arabs together with Berbers, as well Arabized local Visigoths, able spread language Andalusia. In Spain, centers created. From eighth century, when settled area expanded. Cordova, Granada, Almeria, Val...

Let IBn be the set of all irreducible matrices in Bn and let SIBn be the set of all symmetric matrices in IBn. Finding an upper bound for the set of indices of matrices in IBn and SIBn and determining gaps in the set of indices of matrices in IBn and SIBn has been studied by many researchers. In this paper, we establish a best upper bound for the set of weak exponents of indecomposability of ma...