Average fixed cost

Average variable cost

Short-run average cost

Short-run marginal cost

The AFC at each output equals the gap between the SAC and AVC curves at that output

The SMC curve lies above the MVC curve

The MVC curve intersects the lowest point on the AVC curve

The SMC curve intersects the lowest point on the SAC curve

If extra units of one variable input are added to a fixed amount of all other inputs, then sooner or later the marginal returns will get smaller

If extra units of one variable input are added to a fixed amount of all other inputs, then the marginal returns will always get smaller

If extra units of all variable inputs are added to a fixed amount of all fixed inputs, then the marginal returns will always get smaller

If extra units of all variable inputs are added to a fixed amount of all fixed inputs, then sooner or later the marginal returns will get smaller

A firm may have economies of scale, even if it does not have increasing returns to scale

A firm may initially have economies of scale and later have diseconomies of scale

An industry where economies of scale are exhausted at an output that is low relative to the industry output may have many small firms

Throughout the output range where a firm enjoys economies of scale, its long-run marginal cost curve, LMC, will slope downwards

Its SAC curve will stay put if the price of an input that is fixed in the short run increases

Its SAC curve will shift upwards it the price of an input that is variable in the short run increases

Its SAC curve will generally lie above its LAC curve

Its LAC curve will shift upwards if new firms enter its industry and there are external diseconomies of scale