It posits that a 100% tax rate would not garner the government any revenue because individuals would have no incentive to work if all their income was taken.  
Under the Greenwood-Hercowitz-Huffman model, this is heavily dependent upon the Frisch labor supply elasticity.  Ben Stein once claimed that it was supported by "no substantial backup of data at all that [he was] aware of", and Martin Gardner satirized its supposed simplicity by creating a "neo" version of this with multiple local maxima.  It posits that a 100% tax rate would not garner the government any revenue because individuals would have no incentive to work if all their income was taken.  For 10 points, name this illustration that maximum revenue occurs at a tax percentage between 0 and 100% that became a tenet of Ronald Reagan's supply-side economics.
Under the Greenwood-Hercowitz-Huffman model, this is heavily dependent upon the Frisch labor supply elasticity.  
{Laffer curve}