the claim that, other things being equal, the quantity supplied of a good increases when the price of that good rises

The claim that, other things being equal, the quantity supplied of a good increases when the price of that good rises is called the Law of Supply. This fundamental economic principle states that there is a direct relationship between price and quantity supplied: as price rises, producers are willing to supply more of the good, and conversely, when price falls, the quantity supplied decreases. This behavior is driven by the incentive for producers to maximize profits by producing more when prices are higher.