F = Ā·B + A·B̄ — SOP and POS

coreXOR in canonical form

Answer

Σm(1,2) = ΠM(0,3)

Why this example is worth doing

XOR written out as a canonical sum, Σm(1,2), and its POS partner ΠM(0,3). The page's point is that the canonical forms are unique — every function has exactly one canonical SOP and one canonical POS — whereas minimal forms need not be. That uniqueness is what makes canonical forms the right thing to compare when you want to prove two expressions equal, and it is why the equivalence checker on this site normalises to canonical form rather than trying to rewrite one expression into the other.

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 + A · B′

Canonical product of sums

(A + B) · (A′ + B′)

Truth table

Truth table — columns #, A, B, F
#ABF
0000
1011
2101
3110

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)