Regulator
The regulator of a number field K is a positive number associated with K. The regulator of an imaginary quadratic field is 1 and that of a real quadratic, imaginary cubic, or totally imaginary cubic field is the natural logarithm of the field's fundamental unit, i.e.,
| r(d)=lneta(d). |
There is also a more complicated definition for a general number field K as the determinant of an r×r matrix, where K has r_1 real embeddings and 2r_2 imaginary embeddings and r=r_1+r_2-1.
The regulator is implemented in the Wolfram Language for example as NumberFieldRegulator [Sqrt[d]].
See also
Fundamental Unit, Number FieldThis entry contributed by David Terr
Explore with Wolfram|Alpha
More things to try:
Cite this as:
Terr, David. "Regulator." From MathWorld--A Wolfram Resource, created by Eric W. Weisstein. https://mathworld.wolfram.com/Regulator.html