# 'alpha' inside a \def

the following code

\def\AIR{\alphair}


results in a compilation error in Texmaker when calling \AIR\ in text:

"\textit{\AIR\/}"
! Undefined control sequence.\AIR ->\alphair


Where's the problem with MikTex?

## migrated from stackoverflow.comDec 14 '11 at 16:46

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• Have you defined \alphair elsewhere or is it defined in a package you load? Maybe you misspelled \alpha? – N.N. Dec 14 '11 at 14:57
• Well, shouldn't he detect the single \alpha in \alphair ? But also, \def\AIR{\alpha} doesn't work, ofc amssymb is used. – PaddyG Dec 14 '11 at 15:25
• If you write \alphair it's considered as one macro, namely the macro named "alphair". Is what you want to write the symbol alpha followed by "i" and "r"? In that case simply add a space to the definition: \def\AIR{\alpha ir}. – N.N. Dec 14 '11 at 15:40
• Welcome to TeX.sx! Your question was migrated here from Stack Overflow. Please register on this site, too, and make sure that both accounts are associated with each other, otherwise you won't be able to comment on or accept answers or edit your question. – N.N. Dec 14 '11 at 17:07

## 2 Answers

There is nothing wrong with your definition. The problem is that \alphair is not defined.

You probably want to define

\newcommand{\AIR}{$\alpha$\textit{ir}}