Latex Code for One Set Minus Another .... .... A\B .... ....

[Math Amateur]

Recently I posted the following text on the Analysis forum ..." ... ... In order to demonstrate that $$K$$ is closed, we prove that $$\mathbb{R}^n\K$$ is open. Indeed, choose $$y \notin K$$ and define $$O_j = \{ x \in \mathbb{R}^n \ \mid \ \mid \mid x - y \mid \mid \gt \frac{1}{j} \}$$ for $$j \in \mathbb{N}$$. ... ... "... and (as I did above) got a red \K in \mathbb{R}^n\K presumably because I'm misusing a special character \ in the code ...

What is wrong with what I've done and how do I correct it?

Further, how does one correctly write Latex code for one set minus another as in A\B?

Peter

 

[MarkFL]

This works, although there might be a better solution...

\mathbb{R}^n\text{\\}K

gives:

$$\mathbb{R}^n\text{\\}K$$

 

[Math Amateur]

This works, although there might be a better solution...

\mathbb{R}^n\text{\\}K

gives:

$$\mathbb{R}^n\text{\\}K$$

Thanks Mark ... but seems strange to me that two \s are required in text{ \\ } ... but then ... hey ... that's the rules of the code :)

Thanks again ...

Peter

 

[MarkFL]

Thanks Mark ... but seems strange to me that two \s are required in text{ \\ } ... but then ... hey ... that's the rules of the code :)

Thanks again ...

Peter

Yeah, you have to escape the escape character to get a literal character. :)

You can also use:

\mathbb{R}^n\backslash K

or:

\mathbb{R}^n\setminus K (this one has more padding to the left and right of the slash)

 

[MarkFL]

I also want to point out that in the "MHB Widgets" block to the right of the editor is "Detexify" listed as the second entry in the list, and clicking that will popup a window into which you can draw a character you wish to use, and it will give you in most cases several options to try. (Yes)

 

[Evgeny.Makarov]

\mathbb{R}^n\setminus K (this one has more padding to the left and right of the slash)

This is the correct solution.

What is wrong with what I've done and how do I correct it?

The command \K is undefined. TeX commands usually consist of a backslash followed by letters.