A quadratic field, denoted Q(sqrt(D)), is the set of numbers of the form a + b sqrt(D), where a,b are rational numbers.
A quadratic field is denoted Q(sqrt(D))
Integers of a quadratic field are numbers of the form
r + s sqrt(D), if D≡2,3 (mod 4), or
r + s (1/2)(-1 + sqrt(D)), if D≡1 (mod 4),
where r, s are integers.
Gaussian integers are integers of the imaginary quadratic field Q(sqrt(-1))
Eisenstein integers are integers of the imaginary quadratic field Q(sqrt(-3))
. . . . . .
Mathworld: Quadratic Field
Fact archive: Quadratic field, and Heegner number - an imaginary quadratic field with class number 1 (See Ideal class group).
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