F(A,B,C,D,E,F) = Σm(0,2,8,10,16,18,24,26,32,34,40,42,48,50,56,58) — Quine–McCluskey

edge case1 prime implicants, 1 essential

Answer

D′ · F′

Why this example is worth doing

Sixteen minterms over six variables that collapse to a single two-literal product, because the pattern is regular: C and F are 0 in every one of them and nothing else is constrained. It is here to show the tabulation surviving a problem no one would attempt on a map — four planes of K-map, and a chart that would take a page to draw — while producing an answer that fits on one line. It is also the size at which the page starts reporting run time, and where the exact/heuristic threshold becomes worth explaining.

Try your own input in the Quine–McCluskey solver. Minimise past the K-map limit with the full tabular method and Petrick’s step.

How the answer is reached

Quine–McCluskey

Prime implicants — Quine–McCluskey
#Term
1D′ · F′
Minimum cover — Quine–McCluskey
#Cover
1D′ · F′
Warning:

1 term(s), 2 literal(s); 1 essential prime implicant(s).

Truth table

Truth table — columns #, A, B, C, D, E, F, F
#ABCDEFF
00000001
10000010
20000101
30000110
40001000
50001010
60001100
70001110
80010001
90010010
100010101
110010110
120011000
130011010
140011100
150011110
160100001
170100010
180100101
190100110
200101000
210101010
220101100
230101110
240110001
250110010
260110101
270110110
280111000
290111010
300111100
310111110
Warning:

First 32 of 64 rows.

Compare with

Open this example in the Quine–McCluskey solver

The field arrives filled in with this example’s input.

Note:

Notation this page assumes

  • Symbols: · is AND, + is OR, ⊕ is XOR, a prime or an overline is NOT. The field also takes ∧ ∨ ¬ ~ ! & | and the words.
  • Operator precedence, tightest first: NOT, then AND (including juxtaposition), then XOR/XNOR, then NAND/NOR, then OR, then IMPLIES, then IFF.
  • In a minterm index the first variable is the most significant bit, so over [A, B, C] minterm 5 is A·B̄·C.

Sources

  • Quine, “The Problem of Simplifying Truth Functions” (1952)
  • McCluskey, “Minimization of Boolean Functions” (1956)
  • Petrick, “A Direct Determination of the Irredundant Forms” (1956)