Different Types
It is important to note that when speaking about substitute goods we are speaking about two different kinds of goods; so the "substitutability" of one good for another is always a matter of degree. One good is a perfect substitute for another only if it can be used in exactly the same way. In that case the utility of a combination is an increasing function of the sum of the two amounts, and theoretically, in the case of a price difference, there would be no demand for the more expensive good.
In microeconomics, two types of substitutes are being distinguished, gross substitutes and net substitutes. Good is said to be gross substitute of good if
Goods X and Y are said to be net substitutes if
where is a utility function for the two goods.
Read more about this topic: Substitute Good
Famous quotes containing the word types:
“He’s one of those know-it-all types that, if you flatter the wig off him, he chatter like a goony bird at mating time.”
—Michael Blankfort. Lewis Milestone. Johnson (Reginald Gardner)
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)