Original sentence: An optimal tax rate therefore lies somewhere in between.Increasing taxes beyond this optimal point (the peak of the Laffer curve) has the effect of decreases in tax revenue.The Laffer curve is central to supply side economics, as it presents a strong argument for why lowering taxation can actually increase tax revenues.The Laffer curve is merely an application of the general economic law of diminishing returns to tax revenues
Edited sentence: An optimal tax rate is therefore assumed to lie somewhere in between.Increasing taxes beyond this optimal point (the peak of the Laffer curve) is assumed to decrease tax revenue.Many economists have questioned the utility of the Laffer Curve.The Laffer curve is central to supply side economics, as it provides an argument for why lowering taxation may actually increase tax revenues