Definitions for two-level simplification
Implicant
- Single element of ON-set or of don’t care set or any group of these elements that can be combined to form a subcube
Prime implicant
- Implicant that can't be combined with another to form a larger subcube
Essential prime implicant
- Prime implicant is essential if it alone covers an element of ON-set
- Will participate in ALL possible covers of the ON-set
- Don’t care set used to form prime implicants but not to make implicant essential
Objective:
- grow implicant into prime implicants (minimize literals per term)
- cover the ON-set with as few prime implicants as possible (minimize number of product terms)