Complex sentence: His later studies centred mainly on the theory of differentiable economies, where he showed that, in general, aggregate excess demand functions vanish at a finite number of point-basically, showing that economies have a finite number of price equilibria.
Split into simpler sentences: His later studies centred mainly on the theory of differentiable economies where he showed that in general aggregate excess demand functions vanish at a finite number of points. Basically, showing that economies have a finite number of price equilibria.