V-Branch: A generalized utility function

Much of the work in demand theory is restricted by the functional form of the relationship The S-Branch utility function, which is a generalization of the linear expenditure system, corrects many of the restrictions. Many faults, however, still exist. The Allen partial elasticities of substitution are equal and constant for all commodities from different subsets of the function. The V-Branch utility function corrects many of these faults. The Allen partial elasticities of substitution are not restricted to be constant or equal either within or between commodity subsets. They vary according to the amount consumed of each commodity.