Logical conjunction

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This page belongs to resource collections on Logic and Inquiry.

Logical conjunction is an operation on two logical values, typically the values of two propositions, that produces a value of true if and only if both of its operands are true.

A logical conjunction of propositions p and q may be written in various ways.  Among the most common are these:

  • p ~\mathrm{and}~ q
  • p \land q
  • p \cdot q
  • p~q
  • pq

A truth table for p \land q appears below:

\text{Logical Conjunction}
p q p \land q
\mathrm{F} \mathrm{F} \mathrm{F}
\mathrm{F} \mathrm{T} \mathrm{F}
\mathrm{T} \mathrm{F} \mathrm{F}
\mathrm{T} \mathrm{T} \mathrm{T}

A logical graph for p \land q is drawn as two letters attached to a root node:

Cactus Graph Existential P And Q.jpg

Written as a string, this is just the concatenation pq.  The proposition pq may be taken as a Boolean function f(p, q) having the abstract type f : \mathbb{B} \times \mathbb{B} \to \mathbb{B}, where \mathbb{B} = \{ 0, 1 \} is interpreted in such a way that 0 means \mathrm{false} and 1 means \mathrm{true}.

A Venn diagram for p \land q indicates the region, in this case a single cell, where pq is true by means of a distinct color or shading, as shown below:

Venn Diagram P And Q.jpg


Focal nodes

Peer nodes

Logical operators

Related topics

Relational concepts

Information, Inquiry

Related articles

Document history

Portions of the above article were adapted from the following sources under the GNU Free Documentation License, under other applicable licenses, or by permission of the copyright holders.