Possessive expression

Today I am learning about possessive expression called الإضَافَةُ. The term الإضَافَةُ means adding, that is, to add one noun to another to form a relationship of possession or belonging as shown below:

1. Possession
   1. كِتَابُ الْمُدَرِّسِ The teacher's book (or Book of the teacher).
   2. قَلَمُ مُحَمَّدٍ Muhammad's pen (or Pen of Muhammad).
2. Belonging
   1. مَدِيْنَةُ رُوْمَا The city of Rom (or Rom's city).
   2. قِمَّةُ الْجَبَلِ The top of the mountain (or The mountain's top).

About الإضَافَةُ (possessive expression)

1. Both words of a الإضَافَةُ must be nouns.
2. The possessor is called مُضَافٌ إِلَيْهِ while the possessed is called مُضَافٌ. Thus, if we say قَلَمُ مُحَمَّدٌ, then مُحَمَّدٌ is the مُضَافٌ إِلَيْهِ while قَلَمٌ is the مُضَافٌ.
3. The first word must be the مُضَافٌ and the second word must be the مُضَافٌ إِلَيْهِ.

About the مُضَافٌ (possessed)

1. Although the مُضَافٌ does not come with article ال, it is implied. Thus, it means, for example, 'the book' and not 'a book'.
2. The مُضَافٌ can end with dhammah, fathah or kasrah depending on its usage in a sentence. It, however, cannot end with tanwin.

About the مُضَافٌ إِلَيْهِ (possessor)

1. The مُضَافٌ إِلَيْهِ  can be definite or indefinite, for example, الْوَلَدُ (the boy) or وَلَدٌ (a boy)
2. The مُضَافٌ إِلَيْهِ must always be in the genitive case, that is, the last vowel must be a kasrah or kasratain, for example الْمُدَرِّسِ or مُحَمَّدٍ.