# Representation of Three-Valued Boolean Functions

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This Demonstration displays three-valued Boolean functions of arguments. If , the disjunctive normal form (DNF) of a function is also given. If , a random function is given.

Contributed by: Izidor Hafner (September 2016)

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

A three-valued logic function of arguments is represented by . There are such functions; if , there are nine and if , there are 19,683.

The roles of conjunction and disjunction are played by the functions and .

Define three functions for :

if and 0 otherwise.

Each function of arguments can be represented in disjunctive normal form (DNF):

,

where and the maximum is taken over all tuples with components from .

It follows that the constants 0, 1, 2 together with the functions , and form a basis for three-valued Boolean functions [2, pp. 245–246].

In 1936, SŁupecki [1, pp. 335–337] showed that all three-valued functions could be defined using implication and negation from Łukasiewicz three-valued logic plus the constant function called "tertium", 1.

In -valued logic, the Sheffer–Webb function (an analog of the Sheffer stroke function, NAND) forms a basis for -valued logic [2, p. 247].

References

[1] M. Gardner, *Logic Machines, Diagrams and Boolean Algebra*, New York: Dover Publications, 1968.

[2] S. G. Gindikin, *Algebraic Logic in Problems* (in Russian), Moscow: Nauka Publishers, 1972.

[3] J. SŁupecki, "The Full Three-Valued Propositional Calculus,"* Polish Logic 1920–1930*, S. McCall (ed.), Oxford: Oxford University Press, 1967.

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