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Material nonimplication - Wikipedia
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Material nonimplication

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Material nonimplication
NIMPLY
Venn diagram of Material nonimplication
Definitionxy‾
Truth table(0100)
Logic gate
Normal forms
Disjunctivexy‾
Conjunctivex+y‾
Zhegalkin polynomialx⊕xy
Post's lattices
0-preservingyes
1-preservingno
Monotoneno
Affineno
Self-dualno

Material nonimplication or abjunction (from Latin ab 'away' and junctio 'to join') is a term referring to a logic operation used in generic circuits and Boolean algebra.[1] It is the negation of material implication. That is to say that for any two propositions P and Q, the material nonimplication from P to Q is true if and only if the negation of the material implication from P to Q is true. This is more naturally stated as that the material nonimplication from P to Q is true only if P is true and Q is false.

It may be written using logical notation as P↛Q, P⊅Q, or "Lpq" (in Bocheński notation), and is logically equivalent to ¬(P→Q), and P∧¬Q.

Definition

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Truth table

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PQP↛Q
FFF
FTF
TFT
TTF

Logical equivalences

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Material nonimplication may be defined as the negation of material implication.

P↛Q   ⇔   ¬(P→Q)
  ⇔   ¬

In classical logic, it is also equivalent to the negation of the disjunction of ¬P and Q, and also the conjunction of P and ¬Q

P↛Q   ⇔   ¬( ¬P ∨ Q)   ⇔   P ∧ ¬Q
  ⇔   ¬( ∨ )   ⇔   ∧

Properties

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falsehood-preserving: The interpretation under which all variables are assigned a truth value of "false" produces a truth value of "false" as a result of material nonimplication.

Symbol

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The symbol for material nonimplication is simply a crossed-out material implication symbol. Its Unicode symbol is 219B16 (8603 decimal): ↛.

Natural language

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Grammatical

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"p minus q."

"p without q."

Rhetorical

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"p but not q."

"q is false, in spite of p."

Computer science

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Bitwise operation: P & ~Q. This is usually called "bit clear" (BIC) or "and not" (ANDN).

Logical operation: P && !Q.

See also

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References

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  1. ↑ Berco, Dan; Ang, Diing Shenp; Kalaga, Pranav Sairam (2020). "Programmable Photoelectric Memristor Gates for In Situ Image Compression". Advanced Intelligent Systems. 2 (9): 5. doi:10.1002/aisy.202000079.
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