«والموجبة الجزئية تنعكس إلى موجبة جزئية»
A particular affirmative converts to another particular affirmative.
Textbook example:
«بعض الحيوان إنسان»
Some animals are humans.
Its converse:
«بعض الإنسان حيوان»
Some humans are animals.
A shared member belongs to both classes regardless of which is mentioned first. This is why particular affirmation is preserved under conversion.