Given a boolean function that requires n parameters and returns a boolean value, a minterm is a conjunction of all n parameters. Similarly, a maxterm in this context is a disjunction of all n parameters. Note that in both a minterm and a maxterm, each variable must appear once and only once with the optional use of negation.
Let us use exclusive-or as an example. The truth table is displayed in table 1.
In this case, there are four possible minterms, AB, AB′, A′B and A′B′. There are four possible maxterms, A + B, A + B′, A′ + B and A′ + B′.
One way to express exclusive or is to use the disjunction of two minterms: A′B + AB′. We can also express exclusive or using the product of two maxterms: (A + B)(A′ + B′).