# How to make Polish letters capitalized at the beginning of each page in amsbook?

I've been lately struggling with Polish letters in my thesis. Everything is fine in the text itself, but when I compile, the titles at the beginning of each page are displayed incorrectly. Let me show you what I mean.

"ś" and "ń" should be capitalized like the rest of the letters. "Pierścień Burnside'a" is a title of this chapter, of course. My thesis contain the following packages:

\usepackage[english, polish]{babel}
\usepackage{polski}
\usepackage[utf8]{inputenc}

Is this the blame of packages or is it something inside amsbook class? How can it be fixed? Thank you in advance for your help.

Here's an MWE -- please check out the header line on page 2.

\documentclass{amsbook}
%% (uncommenting the next four lines doesn't affect the header line)
%\usepackage[english, polish]{babel}
%\usepackage{polski}
%\usepackage[utf8]{inputenc}
%\usepackage[T1]{fontenc}
\usepackage{lipsum} % for filler text

\begin{document}
\chapter{Pierścień Burnside'a}
\lipsum[1-5] % generate slightly more than 1 page of filler text
\end{document}

• Welcome to TeX SX! Didn't you load \usepackage[T1]{fontenc}? B.t.w., unless you have a old installation loading inputenc is not necessary: utf8 is the default for LaTeX now. Sep 14 '20 at 9:02
• Welcome to TeX.SE! Please show us a short compilable TeX code resulting in your issue, then we do not have to guess what you are doing .... Sep 14 '20 at 9:07
• I've taken the liberty of adding an MWE (minimum working example) that generates the problem behavior you wish to fix. Please feel free to modify the MWE as you see fit.
– Mico
Sep 14 '20 at 9:12
• I did try loading \usepackage[T1]{fontenc}, but it does not fix the problem. Also - thank you for adding MWE. Sep 14 '20 at 9:20
• I'd say the problem is amsbook uppercases strings with \uppercase instead of \MakeUppercase. I'm not sure how to fix it. Sep 14 '20 at 14:50

Compiling the MWE under either XeLaTeX or LuaLaTeX succeeds in getting the capitalization of accented characters in the header line right.

\documentclass{amsbook}
\usepackage[english, polish]{babel}
\usepackage{lipsum}

\begin{document}
\chapter{Pierścień Burnside'a}
\lipsum[1-5]
\end{document}

• Thank you! It worked. But what if I wanted to keep charter font? When I switch to XeLaTeX or LuaLaTeX and use charter, polish signs are erased from entire document. Sep 14 '20 at 10:56
• What operating system do you employ. If it's MacOS, you should be able to use the desired text font by running \usepackage{fontspec} and \setmainfont{Charter}.
– Mico
Sep 14 '20 at 15:18