# Math symbol

1. Nov 15, 2008

### db1uover

What symbol is a small vertical bar with an arrow? I know a plain arrow is "determines". Is there a good site that lists the vocabulary of mathematicians?

2. Nov 15, 2008

### symbolipoint

If you exactly mean that description as a mathematical symbol, I'm not sure; but (assuming the arrow head points upward) if it's a text symbol used in computer programming, your description would mean "exponentiation"; if your symbol is actually used in writing chemical reactions, it would mean "as a gas" when written to the right-hand side of a chemical compound.

3. Nov 15, 2008

### tiny-tim

Hi db1uover!

Do you mean $\uparrow$ ?

If so, I think it only means "spin-up" (for spinors).

btw, if you're really into symbols, bookmark http://www.physics.udel.edu/~dubois/lshort2e/node61.html#SECTION008100000000000000000 [Broken]

Last edited by a moderator: May 3, 2017
4. Nov 15, 2008

### Hootenanny

Staff Emeritus
Alternatively, the symbol $\mapsto$ means "maps to" and is used when defining functions and performing http://en.wikipedia.org/wiki/Map_(mathematics)" [Broken]

Last edited by a moderator: May 3, 2017
5. Nov 17, 2008

### db1uover

Thank you all. Hootenanny, that is what I was looking for, the mathematical verbage. So, the difference between 'maps to' and 'determines' is one is already in place while the other is being fleshed out?

6. Nov 17, 2008

### cristo

Staff Emeritus
Not sure what you are asking, but the difference between $\to$ and $\mapsto$ is best described by an example. So, say, the real function f(x)=x^2 would be expressed as $f:\mathbb{R}\to\mathbb{R}, x\mapsto x^2$

7. Nov 17, 2008

### db1uover

Is this read as 'function f such that Real determines Real when x maps to x squared'? I'm out of school, but trying to remember standard math-ese.

8. Nov 17, 2008

### Hurkyl

Staff Emeritus
I've also seen that symbol used to refer to injections. e.g. Rather than write $X \to Y$, you write $X \mapsto Y$ to state that the map is actually monic.

9. Nov 17, 2008

### CRGreathouse

I read it as "a function f from the reals to the reals that maps x to x squared", or more likely "a function f from R to R that maps x to x squared".

I haven't seen it used in Hurkyl's sense.