The schedule of the Constitution that divides legislative powers between the Union and the States through three lists: the Union List, the State List, and the Concurrent List.
The three lists, the residuary power resting with the Union, and the Concurrent-List supremacy rule are central federalism facts; police and public order being State subjects is the basis for the security-deployment debate.
Police and public order are State List subjects, which is why the CAPFs are deployed only on Centre-State coordination; education was moved from the State List to the Concurrent List by the 42nd Amendment, 1976.
Article 246 plus Seventh Schedule: Union List, State List, Concurrent List; residuary powers with the Union (Article 248).