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Field Trace


The field trace Tr_(L/K)(a) in a finite extension L/K is the matrix trace of the K-linear transformation x|->ax on L. For a separable extension, it equals the sum of the images of a under the field embeddings of L into an algebraic closure of K. For example, Tr_(Q(sqrt(2))/Q)(u+vsqrt(2))=2u (Milne 2020).


See also

Field Norm, Finite Extension, Matrix Trace, Number Field Discriminant

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References

Milne, J. S. "Algebraic Number Theory." 19 Jul 2020. https://www.jmilne.org/math/CourseNotes/ANT.pdf.

Cite this as:

Weisstein, Eric W. "Field Trace." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/FieldTrace.html

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