Rrerku

Unfortunately, the command Alpha does not produce capital version of alpha (as one might expect in analogy with how, say, Pi produces capital pi). It so happens that the capital alpha looks rather similar to A, but that doesn't mean that there aren't situations where I would like to use capital alpha in a formula. For instance, suppose I already have pi which belongs to a set Pi, and then alpha comes along and I need a name for the set of its possible values.

What is the best way to write capital alpha?

The obvious first attempt is to just write A. But it's not right - A produces italic A, while Greek letters are by default not italic. Would mathrmA do the trick, or is there some subtle issue I'm not noticing? Is there a package that will save me the work of defining all capital letters by hand?

Screenshot from lshort.pdf (The Not So Short Introduction to LaTeX2e):

So it is simply mathrmA.

documentclassstandalone
newcommandAlphamathrmA
begindocument
$Alpha+Pi=Gamma$
enddocument

If you're using LuaLaTeX or XeLaTeX, you can use the unicode-math package. It defines all uppercase Greek letters:

documentclassarticle
usepackageunicode-math
begindocument
$Alpha+Beta=Gamma$.
enddocument

The result is:

This way has an advantage in that one can change the style of the letters by altering the unicode-math options. For example usepackage[math-style=ISO]unicode-math without any other changes yields:

Also, this way alpha can be copied&pasted from the resulting PDF.