\MakeLowercase in \section

I need to have a single lower case letter in the section command. The general advice that I have found repeatedly here is to use \MakeLowercase. However, the following extremely simple example already doesn't work.

It produces exactly the same output as

What am I missing?

The definition of \section in amsart.cls is \normalfont\scshape\centering, so we only need to change \scshape to \upshape.



It's not uppercase, but it's small caps lowercase.

Use \textnormal{a1}. But if you have several of these problems, it's better to define a command for them.



Maybe you can decide later that such sections should be unnumbered, or for a different way to typeset the header. Using a command makes this easy.