Heather,

First, I'm assuming you mean "complement" and not "compliment" :) Second, I'm not exactly sure what you mean by complement. I'm guessing that what you mean is $d'$ (which I just typeset using `[[$d'$]]`). Even though the complement of a set $A$ is denoted $A'$, that doesn't mean that every time you see a "prime" on a symbol that it means "complement." You should read $d'$ as "d prime". Usually, we use the "prime" notation to denote an object that is similar to the one without the "prime" but may be different.

Also, I'm pretty sure that the definition of GCD occurs in the next chapter, so it might be best to move that definition to the chapter 1 summary. Just cut the current entry from the chapter 0 summary and paste it into the chapter 1 summary.

When you edit any page, you can put the cursor wherever you want and start typing. So, to put a definition in the "definitions" section, just put the cursor below `+ definitions` in the edit box.

Lastly, to obtain $d'|d$ you would type `[[$d'|d$]]`, where the symbol between d' and d is the "pipe" symbol (shift+backslash).