Prime Implicants and Covers
An implicant is a product term that can cover minterms of a function.
A prime implicant is a product term that is not covered by another implicant of the function.
An essential prime implicant is a prime implicant that covers at least one minterm that is not covered by any other prime implicant.
A set of implicants is said to be a cover of a function if each minterm of the function is covered by at least one implicant in the set.
A minimal cover is a cover that contains the smallest number of prime implicants and the smallest number of literals..