According to article IV, how must laws and legal rulings of one state be treated by others others states?

states should not reopening cases which have been conclusively decided by the courts of another state.

Explanation:

According to article IV, laws and legal rulings of one state which has been decided by another state court of law should not be reopened or revisited.

Article IV of the United States Constitution outlines the connection between diverse state, and also the relationship or connections which occur between individual state and the United States Federal government. Article IV also authorized the Congress to allow entry of new states and regulate or control the territories and several other federal land.

The Full Faith and Credit Clause in Article IV obligate states to expand the full faith and credit clause to the public act. The supreme Court validates that this clause incapacitate state from reopening cases which another state court has placed verdict on it