وَالْقَصْرُ الْإِضَافِيُّ يَنْقَسِمُ بِاعْتِبَارِ حَالِ الْمُخَاطَبِ إِلَى ثَلَاثَةِ أَقْسَامٍ
Relative qasr falls into three types according to the hearer's state.
These are ifrad, qalb, and ta‘yin. The decisive difference is not simply the surface sentence but the belief or uncertainty that the listener brings to it.
One listener combines two rival properties, another believes the reverse attribution, and a third is unsure which of two possibilities is right. Restrictive language addresses these different states for different rhetorical purposes.