x i denotes commodities continuous numbers x=(x1, x2,..xL) vector of discrete commodities p=(p1, p2,.pr) vector of prices w= wealth available to be spent The budget constraint pox ∑ Pix≤wxi denotes commodities, continuous numbers x  x1, x2,.... xL  vector of discrete commodities p  p1, p2,....pL  vector of prices w  wealth available to be spent The budget constraint p  x   i1 L pixi  w