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Prime implicants and essential prime implicants on a K-map

Σm(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14) on a four-variable map: the engine finds six prime implicants and covers all ten ones with three of them; the cover and the derived three-term expression are on the map.

A prime implicant is a group of ones on the map that cannot be enlarged; an essential one is a prime implicant that is the only group covering some one. This function, with ten true rows out of sixteen, is the standard exercise for telling the two apart. The engine's reading restates the minterm list, and the table shows the column true on rows 0, 1, 2, 5, 6, 7, 8, 9, 10 and 14, with maxterms ΠM(3, 4, 11, 12, 13, 15).

The checks: not a tautology, counterexample A = FALSE, B = FALSE, C = TRUE, D = TRUE; satisfiable, witness all four inputs FALSE. The simplifier found no law to apply to the minterm list. The converter expands it into a ten-term, 40-literal DNF and a six-clause, 24-literal CNF; gates: 719 NAND, 1247 NOR. The Karnaugh map reports six prime implicants and draws three: NOT B AND NOT C, C AND NOT D and NOT A AND B AND D. Every 1 is covered; the derived expression is the OR of those three groups, exactly equivalent; the other three prime implicants were not needed.

The lesson transfers to rule writing: a rule set often has more candidate clauses than it needs, and the ones worth keeping are those that alone cover some case. Among the drawn groups, cell 9 is covered only by NOT B AND NOT C and cell 14 only by C AND NOT D, which is what makes a group indispensable. The thing to watch is that the engine reports the count of prime implicants and the cover it chose; the Quine-McCluskey comparison page explains how such covers are found when the map is too large to draw.

f := Σm(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14) · output

Exact checks

Always true (tautology)? No Counterexample: A = F, B = F, C = T, D = T · Exhaustively checked and solver cross-checked · 4 rows
Always false (contradiction)? No Counterexample: A = F, B = F, C = F, D = F · Exhaustively checked and solver cross-checked · 1 rows
Can be true? Yes Example assignment: A = F, B = F, C = F, D = F · Exhaustively checked and solver cross-checked · 1 rows

Truth table (16 rows)

Prime implicants and essential prime implicants on a K-map
#ABCDf
0FALSEFALSEFALSEFALSETRUE
1FALSEFALSEFALSETRUETRUE
2FALSEFALSETRUEFALSETRUE
3FALSEFALSETRUETRUEFALSE
4FALSETRUEFALSEFALSEFALSE
5FALSETRUEFALSETRUETRUE
6FALSETRUETRUEFALSETRUE
7FALSETRUETRUETRUETRUE
8TRUEFALSEFALSEFALSETRUE
9TRUEFALSEFALSETRUETRUE
10TRUEFALSETRUEFALSETRUE
11TRUEFALSETRUETRUEFALSE
12TRUETRUEFALSEFALSEFALSE
13TRUETRUEFALSETRUEFALSE
14TRUETRUETRUEFALSETRUE
15TRUETRUETRUETRUEFALSE

Plain-language reading

Beginnerf is true exactly when the truth-table row of (A, B, C, D) is one of the rows 0, 1, 2, 5, 6, 7, 8, 9, 10, and 14.
In every other case, f is false.
About the operators:
- Σm lists the truth-table rows (minterms) where the formula is true. Rows are numbered from 0 with the first listed input as the most significant bit.
Intermediatef is true exactly when the truth-table row of (A, B, C, D) is one of the rows 0, 1, 2, 5, 6, 7, 8, 9, 10, and 14.
In every other case, f is false.
Advancedf is true exactly when the truth-table row of (A, B, C, D) is one of the rows 0, 1, 2, 5, 6, 7, 8, 9, 10, and 14 [canonical sum of minterms (DNF)].
In every other case, f is false.
Formal notation: Σm(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14)

Logic diagram

Prime implicants and essential prime implicants on a K-map Prime implicants and essential prime implicants on a K-map A B C D f Σm(0,1,2,5,6,7,8,9,10,14)ABCD
Prime implicants and essential prime implicants on a K-map Prime implicants and essential prime implicants on a K-map A B C D f Σm(0,1,2,5,6,7,8,9,10,14)ABCD

Simplification, step by step

The engine found no law that shortens this expression; it is already as short as its rewriting laws can make it.

Σm(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14)

Karnaugh map

AB \ CD
00
01
11
10
00
1m0
1m1
0m3
1m2
01
0m4
1m5
1m7
1m6
11
0m12
0m13
0m15
1m14
10
1m8
1m9
0m11
1m10
  1. cells m5, m7NOT A AND B AND D
  2. cells m0, m1, m8, m9NOT B AND NOT C
  3. cells m2, m6, m10, m14C AND NOT D
(NOT A AND B AND D) OR (NOT B AND NOT C) OR (C AND NOT D) · Derived (NOT A AND B AND D) OR (NOT B AND NOT C) OR (C AND NOT D). Exactly equivalent on every assignment.

Minterms and maxterms

f(A, B, C, D) = Σm(0, 1, 2, 5, 6, 7, 8, 9, 10, 14)f(A, B, C, D) = ΠM(3, 4, 11, 12, 13, 15)

Variable order: A, B, C, D · 16 rows

Normal forms

Conjunctive normal form (CNF)

(A OR B OR NOT C OR NOT D) AND (A OR NOT B OR C OR D) AND (NOT A OR B OR NOT C OR NOT D) AND (NOT A OR NOT B OR C OR D) AND (NOT A OR NOT B OR C OR NOT D) AND (NOT A OR NOT B OR NOT C OR NOT D)

6 clauses, 24 literals · complete · Minterm expansion ×1

Disjunctive normal form (DNF)

(A AND B AND C AND NOT D) OR (A AND NOT B AND C AND NOT D) OR (A AND NOT B AND NOT C AND D) OR (A AND NOT B AND NOT C AND NOT D) OR (NOT A AND B AND C AND D) OR (NOT A AND B AND C AND NOT D) OR (NOT A AND B AND NOT C AND D) OR (NOT A AND NOT B AND C AND NOT D) OR (NOT A AND NOT B AND NOT C AND D) OR (NOT A AND NOT B AND NOT C AND NOT D)

10 terms, 40 literals · complete · Minterm expansion ×1

NAND-only and NOR-only

NAND-only form

NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D)))), NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D)))), NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))))), NAND(NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))), NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))), NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D)))), NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D)))), NAND(NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))))), NAND(NAND(NAND(NAND(A, A), NAND(B, B)), NAND(NAND(A, A), NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))))), NAND(NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))), NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))), NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))))))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D)))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))))), NAND(NAND(NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))), NAND(NAND(NAND(A, B), NAND(A, B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))), NAND(NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))), NAND(NAND(NAND(A, B), NAND(A, B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D)))), NAND(NAND(NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D))))), NAND(NAND(NAND(NAND(NAND(A, A), B), NAND(NAND(A, A), B)), NAND(NAND(C, D), NAND(C, D))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), NAND(D, D)), NAND(NAND(C, C), NAND(D, D)))))), NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(NAND(C, C), D), NAND(NAND(C, C), D))))), NAND(NAND(NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))), NAND(NAND(NAND(A, B), NAND(A, B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D))))), NAND(NAND(NAND(NAND(A, NAND(B, B)), NAND(A, NAND(B, B))), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))), NAND(NAND(NAND(A, B), NAND(A, B)), NAND(NAND(C, NAND(D, D)), NAND(C, NAND(D, D)))))))))

719 gates · verified equivalent on every row

NOR-only form

NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))))), NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))))), NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))))), NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, D), NOR(C, D))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(A, B), NOR(A, B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))))), NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))), NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))))), NOR(NOR(NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D))))), NOR(NOR(NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D)))), NOR(NOR(NOR(NOR(A, NOR(B, B)), NOR(A, NOR(B, B))), NOR(NOR(NOR(C, C), NOR(D, D)), NOR(NOR(C, C), NOR(D, D)))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, D), NOR(C, D))))), NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(C, NOR(D, D)), NOR(C, NOR(D, D)))))), NOR(NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))), NOR(NOR(NOR(NOR(NOR(A, A), B), NOR(NOR(A, A), B)), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D))), NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(A, A), NOR(B, B))), NOR(NOR(NOR(C, C), D), NOR(NOR(C, C), D)))))))))

1247 gates · verified equivalent on every row

The same rule as code

Python
# -*- coding: utf-8 -*-
# Generated by Tangibool (tangibool.python/1). Do not edit by hand; regenerate from the source revision.
# Model: not stated
# Source revision: reference
# Interpretation status: not stated
"""Tangibool evaluator (decision model).

Generated deterministically from the validated Boolean model; it evaluates exactly that
model. It does not establish that the model is a complete, legal, or safe statement of a
real-world rule, and evaluating examples does not verify the rule.

Source revision: reference
Interpretation status: not stated
Exporter: 1.0.0 (format tangibool.python/1; engine 1.0.0; semantics tangibool-semantics/1)
Logic digest: ef325214daf9b0f28403cccbb84a0f1d7d4e03623823a491a1acd21a45ad2a55
Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78

Inputs (dict keys, declared order) and generated parameter names:
    'A' -> input_A
    'B' -> input_B
    'C' -> input_C
    'D' -> input_D

Outputs (declared order) and their functions:
    'f' -> output_f(inputs)

Assumptions (the declared scope, checked by in_scope(inputs)):
    none; every complete assignment is in scope.

Input contract:
    Every required input must be exactly True or False (type(value) is bool). Missing
    inputs, None, strings, integers (including 0 and 1), and keys that are not declared
    inputs raise InputError before anything is evaluated, including inputs that a
    short-circuiting operator would never read. Results are always bool.

Scope:
    Decision functions raise OutOfScopeError when the inputs violate an assumption; an
    out-of-scope assignment is never turned into a False result. Pass check_scope=False
    to evaluate without the scope check, and use in_scope(inputs) to test it separately.

Usage:

    import tangibool_model as model

    model.evaluate({'A': False, 'B': False, 'C': False, 'D': False})
    # -> {'f': True}
    model.output_f({'A': False, 'B': False, 'C': False, 'D': False})
    # -> True
    model.evaluate({'A': 1, 'B': False, 'C': False, 'D': False})
    # raises InputError: 1 is an int, not a bool
"""

import collections.abc as _abc
from typing import Dict, Mapping, Tuple

__all__ = [
    "MODEL_INFO",
    "IDENTIFIER_MAP",
    "INPUT_NAMES",
    "OUTPUT_NAMES",
    "ASSUMPTIONS",
    "InputError",
    "OutOfScopeError",
    "minterm_index",
    "in_scope",
    "evaluate",
    "output_f",
]

MODEL_INFO = {
    "format": "tangibool.python/1",
    "mode": "decision",
    "model": None,
    "revision": "reference",
    "interpretation": None,
    "exporter": "1.0.0",
    "engine_version": "1.0.0",
    "semantics_version": "tangibool-semantics/1",
    "logic_digest": "ef325214daf9b0f28403cccbb84a0f1d7d4e03623823a491a1acd21a45ad2a55",
    "assumptions_digest": "d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78",
    "primary_output": "f",
    "unused_inputs": (),
    "subcircuits": (),
}

# Stable ID -> generated identifier (reversible mapping; names are exact, escaped strings).
IDENTIFIER_MAP = {
    "v_12fea8c43079": {"kind": "input", "name": "A", "identifier": "input_A"},
    "v_832f20faf920": {"kind": "input", "name": "B", "identifier": "input_B"},
    "v_6006883da7d4": {"kind": "input", "name": "C", "identifier": "input_C"},
    "v_c1488685b630": {"kind": "input", "name": "D", "identifier": "input_D"},
    "f_bdc58c8f4d15": {"kind": "output", "name": "f", "identifier": "output_f"},
}

INPUT_NAMES = ("A", "B", "C", "D")
OUTPUT_NAMES = ("f",)
ASSUMPTIONS = ()

_DECLARED_INPUTS = frozenset(INPUT_NAMES)
_SCOPE_INPUTS = ()
_ASSUMPTION_FORMULAS = {entry["name"]: entry["formula"] for entry in ASSUMPTIONS}


class InputError(ValueError):
    """Raised when inputs are missing, undeclared, or not exactly True/False.

    Every required input must satisfy type(value) is bool. Missing inputs, None, strings,
    integers (including 0 and 1), and keys that are not declared inputs are rejected before
    anything is evaluated. A missing input is never treated as False. The individual problems
    are listed in the problems attribute.
    """

    def __init__(self, problems):
        self.problems = tuple(problems)
        super().__init__("Invalid inputs: " + "; ".join(self.problems))


class OutOfScopeError(ValueError):
    """Raised when the inputs violate the model's assumptions (its declared scope).

    Outside its assumptions the rule has no decision: this error is never a False result.
    The names of the violated assumptions are in the violated attribute.
    """

    def __init__(self, violated):
        self.violated = tuple(violated)
        details = ", ".join(name + " (" + _ASSUMPTION_FORMULAS.get(name, "?") + ")" for name in self.violated)
        super().__init__(
            "Out of scope: the inputs violate "
            + ("assumption " if len(self.violated) == 1 else "assumptions ")
            + details
            + ". The rule has no decision outside its assumptions; this is not a False result."
        )


def _short_repr(value: object) -> str:
    text = repr(value)
    return text if len(text) <= 60 else text[:57] + "..."


def _checked_inputs(inputs: Mapping[str, bool], required: Tuple[str, ...], check_scope: bool) -> Dict[str, bool]:
    """Validate inputs strictly before anything is evaluated and return a plain copy."""
    if type(check_scope) is not bool:
        raise TypeError("check_scope must be True or False")
    if not isinstance(inputs, _abc.Mapping):
        raise InputError(["inputs must be a mapping from input names to True/False, got " + type(inputs).__name__])
    problems = []
    for key in inputs:
        if type(key) is not str or key not in _DECLARED_INPUTS:
            declared = ", ".join(repr(name) for name in INPUT_NAMES) or "none"
            problems.append("undeclared input " + _short_repr(key) + " (declared inputs: " + declared + ")")
    needed = tuple(required) + (_SCOPE_INPUTS if check_scope else ())
    for name in needed:
        if name not in inputs:
            problems.append("missing required input " + repr(name))
    for key, value in inputs.items():
        if type(key) is str and key in _DECLARED_INPUTS and type(value) is not bool:
            problems.append(
                "input " + repr(key) + " must be True or False (type bool), got "
                + type(value).__name__ + " " + _short_repr(value)
            )
    if problems:
        raise InputError(list(dict.fromkeys(problems)))
    return dict(inputs.items())


def _require_bool_args(function: str, pairs: Tuple[Tuple[str, object], ...]) -> None:
    problems = [
        "argument " + repr(name) + " of " + function + " must be True or False (type bool), got "
        + type(value).__name__ + " " + _short_repr(value)
        for name, value in pairs
        if type(value) is not bool
    ]
    if problems:
        raise InputError(problems)


def minterm_index(*values: bool) -> int:
    """Row index of an assignment over a declared variable order.

    The first value is the most significant bit, so all-False is row 0. Used for indexed
    minterm (sum) and maxterm (product) forms.
    """
    index = 0
    for value in values:
        if type(value) is not bool:
            raise InputError(["minterm_index() takes True/False values, got " + type(value).__name__ + " " + _short_repr(value)])
        index = index * 2 + (1 if value else 0)
    return index


def _scope_values(values: Dict[str, bool]) -> Tuple[Tuple[str, bool], ...]:
    """Value of every enabled, confirmed assumption for validated inputs, in declared order."""
    return ()


def _require_in_scope(values: Dict[str, bool]) -> None:
    violated = tuple(name for name, holds in _scope_values(values) if not holds)
    if violated:
        raise OutOfScopeError(violated)


def in_scope(inputs: Mapping[str, bool]) -> bool:
    """True when the inputs satisfy every assumption (the model's declared scope).

    Requires the inputs the assumptions read; raises InputError for invalid inputs.
    """
    values = _checked_inputs(inputs, (), True)
    return all(holds for _, holds in _scope_values(values))


# ---- Formula bodies (inputs are validated by the public functions below) ----


def _compute_output_f(input_A: bool, input_B: bool, input_C: bool, input_D: bool) -> bool:
    """Decision output 'f': \u03a3m(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14)"""
    return minterm_index(input_A, input_B, input_C, input_D) in (0, 1, 2, 5, 6, 7, 8, 9, 10, 14)


# ---- Public API ----


def output_f(inputs: Mapping[str, bool], *, check_scope: bool = True) -> bool:
    """Decision output 'f' (stable ID f_bdc58c8f4d15).

    'f' := \u03a3m(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14)

    Required inputs: 'A', 'B', 'C', 'D'.
    Raises InputError for missing, undeclared, or non-bool inputs, and OutOfScopeError
    when check_scope is True and the inputs violate an assumption.
    """
    values = _checked_inputs(inputs, ("A", "B", "C", "D"), check_scope)
    if check_scope:
        _require_in_scope(values)
    output_f_value = _compute_output_f(values["A"], values["B"], values["C"], values["D"])
    return output_f_value


def evaluate(inputs: Mapping[str, bool], *, check_scope: bool = True) -> Dict[str, bool]:
    """Evaluate every output (declared order); each output is computed once.

    Required inputs: 'A', 'B', 'C', 'D'.
    Raises InputError for missing, undeclared, or non-bool inputs, and OutOfScopeError
    when check_scope is True and the inputs violate an assumption.
    """
    values = _checked_inputs(inputs, ("A", "B", "C", "D"), check_scope)
    if check_scope:
        _require_in_scope(values)
    output_f_value = _compute_output_f(values["A"], values["B"], values["C"], values["D"])
    return {
        "f": output_f_value,
    }
PostgreSQL
-- Tangibool PostgreSQL export (tangibool.postgresql/1)
-- Target: PostgreSQL 16 or later with typed boolean inputs; tested with PostgreSQL 18.3 (PGlite 0.5.8).
-- Not a claim of compatibility with other SQL dialects.
-- Model: not stated
-- Source revision: reference
-- Interpretation status: not stated
-- Exporter: 1.0.0 (engine 1.0.0; semantics tangibool-semantics/1)
-- Logic digest: ef325214daf9b0f28403cccbb84a0f1d7d4e03623823a491a1acd21a45ad2a55
-- Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78
-- Mode: decision
--
-- Read-only: this file contains only WITH / VALUES / SELECT statements. No DDL, DML,
-- procedures, credentials, network access, or database changes. The expressions are pure
-- Boolean expressions, so their result does not depend on SQL evaluation order.
--
-- NON-NULL INPUT PRECONDITION: NULL is not a truth value of this rule. Every fragment below
-- is defined only when every input column it reads is a non-NULL boolean. The guard template
-- (section 2) marks any NULL input as 'invalid_input' and any row that violates the
-- assumptions as 'out_of_scope', and fills output columns only for 'ok' rows; a NULL in an
-- output column of another row is an envelope marker, not a third truth value. Never wrap
-- the fragments in COALESCE(..., FALSE) or otherwise choose a meaning for unknown inputs.
-- This evaluates the supplied model; it does not show that the model is a complete, legal,
-- or safe statement of a real-world rule.
--
-- Input columns (stable ID: name -> column):
--   v_12fea8c43079: A -> "in_A"
--   v_832f20faf920: B -> "in_B"
--   v_6006883da7d4: C -> "in_C"
--   v_c1488685b630: D -> "in_D"
-- Output columns:
--   f_bdc58c8f4d15: f -> "out_f"
-- Assumptions (scope K; exported separately and never folded into an output):
--   none; every complete input row is in scope.

-- ----------------------------------------------------------------------------------------------
-- 1. Expression fragments (parenthesised; non-NULL boolean inputs required)
-- ----------------------------------------------------------------------------------------------
--
-- [out_f] output f (stable ID f_bdc58c8f4d15)
--   f := \u03a3m(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14)
--   PRECONDITION: "in_A", "in_B", "in_C", "in_D" are non-NULL booleans.
--   (((NOT "in_A") AND (NOT "in_B") AND (NOT "in_C") AND (NOT "in_D")) OR ((NOT "in_A") AND (NOT "in_B") AND (NOT "in_C") AND "in_D") OR ((NOT "in_A") AND (NOT "in_B") AND "in_C" AND (NOT "in_D")) OR ((NOT "in_A") AND "in_B" AND (NOT "in_C") AND "in_D") OR ((NOT "in_A") AND "in_B" AND "in_C" AND (NOT "in_D")) OR ((NOT "in_A") AND "in_B" AND "in_C" AND "in_D") OR ("in_A" AND (NOT "in_B") AND (NOT "in_C") AND (NOT "in_D")) OR ("in_A" AND (NOT "in_B") AND (NOT "in_C") AND "in_D") OR ("in_A" AND (NOT "in_B") AND "in_C" AND (NOT "in_D")) OR ("in_A" AND "in_B" AND "in_C" AND (NOT "in_D")))
--

-- ----------------------------------------------------------------------------------------------
-- 2. Guard template (read-only SELECT over an inputs list)
-- ----------------------------------------------------------------------------------------------
-- Replace the example rows between the markers with your own rows, or replace the inputs
-- CTE with a SELECT that provides the boolean columns listed in the header. status is
-- 'invalid_input' when any input is NULL, 'out_of_scope' when the assumptions are false, and
-- 'ok' otherwise; output columns are filled only for 'ok' rows (NULL elsewhere is an
-- envelope marker). Assumption columns are shown for rows with complete inputs.
WITH inputs ("row_id", "in_A", "in_B", "in_C", "in_D") AS (
  -- tangibool:example-rows:begin
  VALUES
    (1, FALSE, FALSE, FALSE, FALSE),
    (2, FALSE, FALSE, FALSE, TRUE),
    (3, FALSE, FALSE, TRUE, FALSE),
    (4, FALSE, FALSE, TRUE, TRUE),
    (5, FALSE, TRUE, FALSE, FALSE),
    (6, FALSE, TRUE, FALSE, TRUE),
    (7, FALSE, TRUE, TRUE, FALSE),
    (8, FALSE, TRUE, TRUE, TRUE),
    (9, TRUE, FALSE, FALSE, FALSE),
    (10, TRUE, FALSE, FALSE, TRUE),
    (11, TRUE, FALSE, TRUE, FALSE),
    (12, TRUE, FALSE, TRUE, TRUE),
    (13, TRUE, TRUE, FALSE, FALSE),
    (14, TRUE, TRUE, FALSE, TRUE),
    (15, TRUE, TRUE, TRUE, FALSE),
    (16, TRUE, TRUE, TRUE, TRUE),
    (17, NULL::boolean, FALSE, FALSE, FALSE)
  -- tangibool:example-rows:end
),
checked AS (
  SELECT
    inputs.*,
    CASE
      WHEN "in_A" IS NULL OR "in_B" IS NULL OR "in_C" IS NULL OR "in_D" IS NULL THEN 'invalid_input'
      ELSE 'ok'
    END AS "status"
  FROM inputs
)
SELECT
  "row_id",
  "in_A",
  "in_B",
  "in_C",
  "in_D",
  "status",
  CASE WHEN "status" = 'ok' THEN (((NOT "in_A") AND (NOT "in_B") AND (NOT "in_C") AND (NOT "in_D")) OR ((NOT "in_A") AND (NOT "in_B") AND (NOT "in_C") AND "in_D") OR ((NOT "in_A") AND (NOT "in_B") AND "in_C" AND (NOT "in_D")) OR ((NOT "in_A") AND "in_B" AND (NOT "in_C") AND "in_D") OR ((NOT "in_A") AND "in_B" AND "in_C" AND (NOT "in_D")) OR ((NOT "in_A") AND "in_B" AND "in_C" AND "in_D") OR ("in_A" AND (NOT "in_B") AND (NOT "in_C") AND (NOT "in_D")) OR ("in_A" AND (NOT "in_B") AND (NOT "in_C") AND "in_D") OR ("in_A" AND (NOT "in_B") AND "in_C" AND (NOT "in_D")) OR ("in_A" AND "in_B" AND "in_C" AND (NOT "in_D"))) END AS "out_f"
FROM checked
ORDER BY "row_id";
SMT-LIB
; Tangibool SMT-LIB export (tangibool.smtlib/1)
; Profile: SMT-LIB 2.6 Boolean subset (QF_UF): Bool constants, define-fun, let, push/pop, assert, check-sat, echo.
; Tested with Z3 5.1.0 (z3-solver 5.2.0, WebAssembly build).
; Model: not stated
; Source revision: reference
; Interpretation status: not stated
; Exporter: 1.0.0 (engine 1.0.0; semantics tangibool-semantics/1)
; Logic digest: ef325214daf9b0f28403cccbb84a0f1d7d4e03623823a491a1acd21a45ad2a55
; Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78
; Mode: decision
;
; Reading results: each query block states what sat and unsat mean for its question. A sat
; answer comes with a witness or counterexample (ask for it with (get-model) after sat only);
; unsat settles that scoped query and is solver-checked, not an independently checked proof
; certificate; unknown settles nothing. Blocks are scoped with push/pop, so assertions never
; accumulate across questions. This checks the supplied model, not whether it is a complete,
; legal, or safe statement of a real-world rule.
;
; Symbols (stable ID: name -> symbol):
;   v_12fea8c43079: A -> in_A
;   v_832f20faf920: B -> in_B
;   v_6006883da7d4: C -> in_C
;   v_c1488685b630: D -> in_D
;   f_bdc58c8f4d15: f -> out_f

(set-option :produce-models true)
(set-info :smt-lib-version 2.6)
(set-logic QF_UF)

; ---- Inputs (declared order)
(declare-const in_A Bool) ; A
(declare-const in_B Bool) ; B
(declare-const in_C Bool) ; C
(declare-const in_D Bool) ; D

; ---- Outputs (dependencies first)
; output f (stable ID f_bdc58c8f4d15): \u03a3m(A, B, C, D; 0, 1, 2, 5, 6, 7, 8, 9, 10, 14)
(define-fun out_f () Bool (or (and (not in_A) (not in_B) (not in_C) (not in_D)) (and (not in_A) (not in_B) (not in_C) in_D) (and (not in_A) (not in_B) in_C (not in_D)) (and (not in_A) in_B (not in_C) in_D) (and (not in_A) in_B in_C (not in_D)) (and (not in_A) in_B in_C in_D) (and in_A (not in_B) (not in_C) (not in_D)) (and in_A (not in_B) (not in_C) in_D) (and in_A (not in_B) in_C (not in_D)) (and in_A in_B in_C (not in_D))))

; ---- Assumptions (the scope K; never folded into an output)
; K: conjunction of the enabled, confirmed assumptions (true when there are none)
(define-fun K () Bool true)

; ---- Definitions only: nothing is asserted and no check is run.
; Add (assert ...) and (check-sat) inside (push 1) ... (pop 1) to ask a question.
LaTeX
f = \sum m_{(A, B, C, D)}(0, 1, 2, 5, 6, 7, 8, 9, 10, 14)

The common slip

Drawing every prime implicant into the expression. Six groups exist, but three of them only cover cells the other three already cover, and including them makes the expression longer without changing a single row. The map's derived result uses the three groups needed, and the table proves it equal to the original.

Questions

How do I tell an essential prime implicant from a merely prime one?

Find a one that lies in only one prime implicant; that implicant is essential. On this map cell 9 and cell 14 each lie in one of the drawn groups. A prime implicant all of whose ones are shared with others is not essential and may be left out if the rest already cover everything.

Related

Tools

See also

Worked examples

Generated from the Tangibool engine, semantics tangibool-semantics/1, engine 1.0.0, build . Every table, map, simplification and verdict on these pages was computed by the Tangibool engine when the site was built, and every claim was re-checked by the same exact checker the app uses. Limits are stated where they apply. © 2026 Foreranger LTD.