"The professor's newspaper is blue."
Translation:صَحيفة اَلْأُسْتاذ زَرْقاء.
If you remember in one of my posts in the forum, I've explained how the definite artilce "AL" plays a major role in defining the nature of relation between 2 words. If we are talking genitive (of-relationship) then the second one in the compound is the one to get "AL" (if the whole compound is defined).
If the compound is not to be defined, then no word gets definite article but one must make sure that the second word has Kasrah (or Tanwin bil Kasr -in if indefinite).
- صحيفة الأستاذِ (CaHífatul-UstaTHi) *The newspaper of the professor.
- صحيفةُ أستاذٍ (CaHífatu UstaThin) a newspaper of a professor