# Any numbers being Complex numbers

1. Jan 9, 2012

### Anachronistic

Are there any numbers that is not considered to be a subset of a complex number subset of

a + bi

Where a and b are real numbers?

2. Jan 9, 2012

### micromass

Define "number".

I'm asking because the concept of number is not well-defined in mathematics. There are a lot of things which carry the name "number", like real number, transfinite number, p-adic number, hyperreal number, etc. All these things are called numbers and often have no obvious relationship to eachother. The concept of a number is too broad. It is not defined in mathematics.

Last edited: Jan 9, 2012
3. Jan 9, 2012

### nonequilibrium

I don't know as much as micromass on this subject, but I just read this on wikipedia and I think it might interest the OP.

On the wiki page of Number, it says under the header "Complex Numbers" the following:
which is the same wording at the OP used, so maybe he chould check out hypercomplex numbers.

4. Jan 9, 2012

### ohwilleke

Numerical quantities described with vectors of more than two elements or tensors cannot, as a general rule, be described as complex numbers.