1. A production function shows the maximum output that can be produced from a given set of inputs over a period of time. It can be expressed as an equation, table, or graph.
2. The Cobb-Douglas production function is an important example that was formulated by Paul Douglas and Charles Cobb. It expresses output as a power function of labor and capital inputs.
3. The law of variable proportions states that as one variable input is increased, initially average and marginal products will increase until diminishing returns set in, after which average and marginal products will decrease.