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Primitive Element


Given algebraic numbers a_1, ..., a_n it is always possible to find a single algebraic number b such that each of a_1, ..., a_n can be expressed as a polynomial in b with rational coefficients. The number b is then called a primitive element of the extension field Q(a_1,...,a_n)/Q. Stated differently, an algebraic number b is a primitive element of Q(a_1,...,a_n)/Q iff Q(a_1,...,a_n)=Q(b). Primitive elements were implemented in version of the Wolfram Language prior to 6 as PrimitiveElement[z, {a1, ..., an}] (after loading the package NumberTheory`PrimitiveElement`.

For example, a primitive element of Q(sqrt(2),sqrt(3))/Q is given by b=sqrt(2)+sqrt(3), with

sqrt(2)=1/2b(b^2-9)
(1)
sqrt(3)=1/2b(11-b^2).
(2)

See also

Extension Field, Primitive Polynomial, Primitive Root

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References

Loos, R. "Computing in Algebraic Extensions." Computing, Suppl. 4, 173-187, 1982.

Referenced on Wolfram|Alpha

Primitive Element

Cite this as:

Weisstein, Eric W. "Primitive Element." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/PrimitiveElement.html

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