F = A·B + C — SOP and POS

introexpand to canonical SOP and POS

Answer

Σm(1,3,5,6,7) = ΠM(0,2,4)

Why this example is worth doing

The basic expansion. A·B is missing C, so it splits into two minterms; C is missing both A and B, so it splits into four, and the union is five distinct minterms. The page shows the multiply-by-(X + X̄) step for each incomplete term, which is the mechanical procedure being examined, and stresses that duplicates collapse by idempotence rather than accumulating. The maxterm list is then simply the complementary index set — the observation that saves half the work on every question of this type.

Try your own input in the SOP & POS canonical forms. Expand to canonical minterms and maxterms, and convert between the two.

How the answer is reached

Canonical sum of products

A′ · B′ · C + A′ · B · C + A · B′ · C + A · B · C′ + A · B · C

Canonical product of sums

(A + B + C) · (A + B′ + C) · (A′ + B + C)

Truth table

Truth table — columns #, A, B, C, F
#ABCF
00000
10011
20100
30111
41000
51011
61101
71111

Compare with

Open this example in the SOP & POS canonical forms

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

  • Shannon, “A Symbolic Analysis of Relay and Switching Circuits” (1938)
  • McCluskey, “Minimization of Boolean Functions” (1956)