Of course, this definition can be extended to any other factors. According to this definition, it is possible for a country to be abundant in more than one factors. The HOV Theorem states that if trade is balanced a country exports all of its abundant factors through trade in goods. If factor prices are equalized, the definition of factor abundance makes sense, since income is the sum of factor incomes. Thus, one can say that the above is a more general definition of factor abundance.
Trade theory is supposed to predict the patterns of output trade.
As the number of outputs increases, it becomes exceedingly difficult to predict the patterns of output trade. Thus, HOV was not even a result that economists were looking for. Nevertheless, HOV theorem predicts the indirect trade of factors through output trade. If HOV prediction is not materialized in the real world, it is an indication that there is a serious distortion in the economy. However, tariffs tend to reduce trade volume, but not reverse commodity trade pattern.