# What is the axis label for the fourth dimension?

1. Dec 25, 2012

### Jow

I have a quick question. On a typical cartesian coordinate system you have the x-axis and y-axis for two dimensions and the z-axis for the third. What would you label the axis representing the fourth dimension?

I know this is a bit of a silly and unimportant question, but I was thinking about function notation (ie: f(x), f(x,y) , f(x,y,z)) and I was wondering what would come next; f(x,y,z,?)

2. Dec 25, 2012

### Mandelbroth

w is the usual convention, but you CAN call it whatever you want.

3. Dec 26, 2012

### HassanEE

Fourth dimension is frequently time--denoted with letter t.

4. Dec 26, 2012

### Number Nine

Physics frequently deals with time-like dimensions, but this isn't particularly common or useful in mathematics, and "time" as a dimension behaves differently than what the OP is asking about. When dealing with, say, Euclidean 4-space, Mandelbroth is right that w is the usual convention, but it's fairly common to just use, say, an indexed family of x's (i.e. x1 ... x4).

5. Dec 27, 2012