Change font of theoremref from italic to normal

Question

I'm using the theoremref package. Some of my sections are numbered with letters, i.e. A, B, C, ... instead of 1, 2, 3, ...

If there is a theorem in, e.g., section A

\begin{Theorem}\thlabel{theo} \end{Theorem}

then the reference looks like the following:

\thref{theo} -> Theorem A.1

Now I would like to change the font of A from italic to normal font.

---

A minimal example can be view here (if anything is missing, please write, it's my first question in the forum :-) ): https://v1.overleaf.com/21643066jhqtrhnhqmwv

Answer 1

Use cleveref instead of theoremref: it's much easier and much better customizable.

\documentclass[reqno,12pt,a4paper]{article}

\usepackage[ngerman]{babel}   % Silbentrennung
\usepackage{url}              % für URLs und Mailadressen  
\usepackage[T1]{fontenc}      % Zeichensatzcodierung
%\usepackage[latin1]{inputenc} % Codepage für Eingabe
\usepackage{amsmath}
\usepackage{amsthm}          % Pakete
\usepackage{amsfonts}               % der
\usepackage{amssymb}                    % AMS
\usepackage{array}            % bessere Tabellendarstellung
\usepackage{graphicx}         % Grafik-Einbindung
\usepackage{extarrows}
%\usepackage{a4wide} 
\usepackage{color}
\usepackage{mathrsfs}
\usepackage{setspace}
\usepackage{multicol}
\usepackage{dsfont}
\usepackage{csquotes}
\usepackage[style=alphabetic ,maxnames=99, mincitenames=4,firstinits=true]{biblatex}

\usepackage{hyperref}
\usepackage[capitalize]{cleveref} %referenzen

\usepackage{enumitem}  %counter enumerate

\pagestyle{plain}             % Zeilennummern unten mittig, kein Header

\numberwithin{equation}{section} %nummerierung der Formeln


\newtheoremstyle{normal}   % name
{11pt}                         % Space above
{11pt}                         % Space below
{\normalfont}                            % Body font
{}                            % Indent amount 1
{\bfseries}                   % Theorem head font
{}                    % Punctuation after theorem head %\newline einsetzen
{.5em}                        % Space after theorem head 2
{}                            % Theorem head spec 
\theoremstyle{linebreak}

\theoremstyle{normal}
\newtheorem{Lemma}{Lemma} \numberwithin{Lemma}{section}
\newtheorem{Bem}[Lemma]{Bemerkung}  
\newtheorem{Def}[Lemma]{Definition}  
\newtheorem{Satz}[Lemma]{Satz}
\newtheorem{Folg}[Lemma]{Folgerung}
\newtheorem{bsp}[Lemma]{Beispiel}
\newtheorem{kor}[Lemma]{Folgerung} 
\newtheorem{Not}[Lemma]{Notation} 
\newtheorem{theo}[Lemma]{Theorem} 
\newtheorem{prob}[Lemma]{Problem} 


\renewcommand{\proofname}{Beweis}

\setcounter{tocdepth}{2} %tiefe Inhaltsverzeichnis

\addbibresource{QuelleDipl.bib}




% erst Nachname, dann Vorname
\DeclareNameAlias{default}{last-first}
% Trenner zwischen den Namen ein Semikolon
\renewcommand*{\multinamedelim}{\addsemicolon\space}
% Doppelpunkt nach dem letzten Namen
\renewcommand*{\labelnamepunct}{\addcolon\space}

\renewcommand*{\multinamedelim}{\addsemicolon\space} 
\renewcommand*{\finalnamedelim}{\addsemicolon\space}

\begin{document}

\renewcommand{\arraystretch}{1.2}
\setstretch {1.5}
\tableofcontents


\newpage
\begin{appendix}
\section{Gebrochen-lineare Transformation von Matrizen}\label{sec:appC}
\renewcommand{\theequation}{\Alph{section}.\arabic{equation}}


\begin{Lemma}\label{zusatz}
Sei $P \in  \mathbb C^{p \times p}$. Dann sind folgende Aussagen äquivalent:
\begin{enumerate}
    \item[(i)] $P$ eine ist  Orthoprojektionsmatrix 
    \item[(ii)]$P^{*}=P=P^{2}$
    \item[(iii)] $I_q-P$ ist eine Orthoprojektionsmatrix.
    \end{enumerate}
\end{Lemma}

Einen ausführlichen Beweis von \cref{zusatz} ...


\end{appendix}

\end{document}

I commented latin1 because my system uses UTF-8 and you should too. The a4wide package has been deprecated for more than a decade: use geometry instead.

As you see, you use the standard \label command and \cref instead of \thref.

By the way, you should set \arraystretch less than 1 with \setstretch{1.5} or matrices will come up very strange. Use

\renewcommand{\arraystretch}{0.66667}

instead.