Latex Math Symbol: Vitanyi puts a tiny plus symbol over his equals. How do I do that?

Question

For example, in http://homepages.cwi.nl/~paulv/papers/algorithmicstatistics.pdf at the bottom of page 5 and top of page 6, he uses a plus/equal symbol and a similar plus/lessthan symbol. I can't figure out how to make that symbol, and I'd like to quote him.

Any help?

Answer 1

Try $\stackrel{top}{bottom}$

You'd want something like this:

$X \stackrel{+}{=} Y$

This positions the plus sign above the equals sign. For example, the following code:

$K(x,y|z) \stackrel{+}{=} K(x|z) \stackrel{+}{<} I(x:y|z)$

produces the following output:

Answer 2

The Comprehensive LaTeX Symbol List (from here) is a great resource, and start for questions like this. You could also contact the author, it's possible he did some LaTex voodoo (math accents and such) to get it to work.

Best of luck.

PS: isn't \pm plus-minus, not plus-equals?