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 Math Help > Sets, Set theory, Number systems > Number systems > Complex Number

Complex numbers are a field, extending the reals to include the square root of -1 and its closure under multiplication and addition.  Complex numbers are an extension of the reals . . . . . .

### Internet references

Wikipedia: Complex number

Mathworld: Complex Number

Fact archive: Complex number

Euclidean Space: complex

Euclidean Space: hypercomplex

### Related pages in this website

Complex, Quaternion, Octonion, and Sedenion numbers are n-tuples of real numbers, where n=2,4,8,16, respectively.

Sums of Squares - Every positive integer can be expressed as the sum of four squares; Primes of the form 4k+1 (and their products using the Complex Product Identity) can be expressed as the sum of two squares; Primes of the form 4k+3 (and their products using the Quaternion Identity) can be expressed as the sum of four squares.

The webmaster and author of this Math Help site is Graeme McRae.