Logic Reduction/Factorization Berkeley’s Espresso (Cont.)
5) A number of other strategies are used to improve the result or to compute it more quickly. These include:
a) Early identification and extraction of essential prime implicants, so they need not be revisited during step 4
b) Using the function's complement to check efficiently whether an expand step actually increases the coverage of the function (the minterms covered by an expanded implicant may already be covered by another expanded implicant, so the newly expanded implicant should not be placed in the cover)
c) A special “last gasp” step which guarantees that no single prime implicant can be added to the cover in such a way that two primes can then be eliminated