Lerner symmetry theorem

The Lerner symmetry theorem, often associated with the economist Abba Lerner, relates to the behavior of taxes and subsidies in an economy. The theorem posits that under certain conditions, the effects of a tax and a subsidy on output can be considered symmetrical. In other words, if a good is taxed, removing the tax (or replacing it with a subsidy) leads to similar effects on the quantity produced and consumed, though the sign of the effect is reversed.