when price elasticity is greater than 1 demand is price elastic
when price elasticity is less than 1 a good is price inelastic
when price elasticity is positive goods are substitutes
when price elasticity is negative goods are compliments
consumer surplus is the welfare enjoyed by the consumer over and above the price paid for the product
derived demand is the demand for a factor of production, wanted not for its own sake, but as a consequence of the production of another good
law of diminishing returns - as a variable factor of production is added to a fixed factor of production, both the marginal physical product and the average physical product will begin to fall
diminishing returns sets in where marginal cost starts sloping upward
static efficiency refers to being efficient at a singular moment in time (especially productive and allocative)
