Is there a way to make the numbering of items non italic. To to be specific in the following example I would like that (v) becomes non italic (italic blablabla is fine).
\documentclass{article} \usepackage{amsthm} \newtheorem{thm}{Theorem} \begin{document} \begin{thm} \begin{enumerate} \item[(v)] blablabla \end{enumerate} \end{thm} \begin{thm} \begin{itemize} \item[(v)] blablabla \end{itemize} \end{thm} \end{document} You can use the start key of enumitem or, better, the series key which makes all enumerate environments in a series to have the same layout and share the same counter. Here I use a thmenum series. Note you may have as many series as you please.
\documentclass{article} \usepackage{amsthm} \usepackage{enumitem}% \newtheorem{thm}{Theorem} \usepackage{etoolbox} \AtBeginEnvironment{thm}{\setlist[enumerate, 1]{font=\upshape, nosep, wide=0.5em, before=\leavevmode}} \begin{document} \begin{thm} \begin{enumerate}[series=thmenum] \item Blablabla \item Bliblibli \end{enumerate} \end{thm} \begin{thm} \begin{enumerate}[thmenum] \item Blablabla \item Bliblibli \item Blobloblo \end{enumerate} \end{thm} \end{document} 
Blablabla, Bliblibli, Blobloblo. :)
\usepackage{enumitem} \setlist[enumerate]{label={\upshape(\roman*)}}one can enumerate upright. Unfortunately in this circumstance, I should enumerate manually.Theorem 1. item 1 item 2,Theorem 2 item 3 item 4 item 5etc.