What does the \ symbol mean, please?

[pellman]

... as in $$\bold{R}^2$$\$$\{\bold{0}\}$$

Used in context here http://books.google.com/books?id=4Y...hsjnCQ&sa=X&oi=book_result&resnum=1&ct=result top of the page.

I've previously seen the notation $$\bold{R}^2-\{\bold{0}\}$$ for the cartesian plane with the origin excluded, so I hesitated to assume that the above notation meant the same thing.

 

[Dragonfall]

It means the same thing as R - {0} Actually "X - Y" as is an old notation back when the term "set arithmetic" was still used. So the modern notation is X\Y.

 

[CRGreathouse]

Ditto. The LaTeX for that operator is \setminus.

 

[pellman]

Thanks and thanks.