complex numbers

number which is a combination of real and imaginary numbers, non-concrete numbers (Mathematics)

number which is a combination of real and imaginary numbers, non-concrete numbers (Mathematics)

In mathematics, a complex number is a number of the form where a and b are real numbers, and i is the imaginary unit, with the property i ² = −1. The real number a is called the real part of the complex number, and the real number b is the imaginary part. Real numbers may be considered to be complex numbers with an imaginary part of zero; that is, the real number a is equivalent to the complex number a+0i.
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Complex numbers are the superset that includes all real and imaginary numbers. A complex number is usually represented by the expression a + ib where a and b are real numbers and i is the imaginary part of the expression where i has the property that i2=-1.
See also, Cross-spectrum Analysis in Time Series .