The equation Is (r ) = S (Y ) had been accepted by the classics, who had viewed it as the condition of equilibrium between supply and demand for investment funds and as determining the interest rate (see the classical theory of interest).
Rovnice Is(r) = S(Y) byla přijata klasiky, kteří ji považovali za podmínku rovnováhy mezi nabídkou a poptávkou po investičních fondech a stanovením úrokové sazby.