# Diagrams

Forums:

I'm interested in drawing a diagram of field extensions with their rings of integers, and I'd like to show the rings of integers as contained in ($\subset$) their field of fractions. Can anyone tell me how to get that symbol used as the 'arrow' connector in an xypic diagram?

Thanks,
Roger

### Re: Diagrams

Thanks!

I conclude from that that there is no standard way to do this. What a shame.

### Re: Diagrams

Could it be {->} as in pstricks?

### Re: Diagrams

Here's a first stab at it: It's a little jury-rigged, but with a little tweaking, would probably look okay.

\begin{align*}
\xymatrix{
\O_L\ar@<.5ex>@{_(-}[r]\ar@<-.7ex>@{-}[r]&L\ar@{-}[d]\\
\O_K\ar@<.5ex>@{_(-}[u]\ar@<-.7ex>@{-}[u]\ar@<.5ex>@{_(-}[r]\ar@<-.7ex>@{-}[r]&K
}
\end{align*}

Cam

### Re: Diagrams

Yeah, so I finally figured this one out. There doesn't appear to be an arrow type that will use the \subset or \supset symbols, but if you just code these as objects, with empty arrows, with some adjustment of the row and column spacing, it looks great! So, for example,

$\xymatrix @C0.25pc@R0.5pc{ B& \subset & L\\ \cup\\ A & \subset & K \ar@{-}[uu]}$

Roger