# Theorem environment doesn't behave the way it was supposed to

I'm using the following template to make a poster.

What I want is to enunciate a theorem with the theorem environment provided by the amsthm package. The problem is, there's some kind of "structure" defined in the file beamerthemeconfposter, which is called a block, and when I use

\newtheorem{theo}{Theorem}
...
\begin{theo}
Theorem
\end{theo}


it creates a new block, whose title is "Theorem". It does not put the theorem inside the new block in the usual way. The

\begin{theo}
...
\end{theo}


is behaving like a

\begin{block}{Theorem}
...
\end{block}


I searched for inside all documents that I downloaded with the template, but couldn't find any clue. The image below (look at the "Riemann-Roch theorem" part) shows the effect (I removed the pictures that come in the main.tex file)

• What about \newenvironment rather than \newtheorem? – user94293 Jun 16 '16 at 4:31
• Welcome to TeX.SX!! Rather than giving code fragments it is better to post a full minimal working example. Currently we have to guess what you're doing and it is difficult reconstruct, and hence fix, your problem from the information in your question. A MWE should start with a \documentclass command, have a minimal preamble and then \begin{document}...\end{document}. The code should compile and be as small as possible to demonstrate your problem. This makes it much easier for people to help you --- and much more likely that they will! – Andrew Jun 16 '16 at 6:39

As beamerposter is based in beamer class, let's dive a little bit inside beameruserguide.

In page 16 we find:

Therefore, we jump to section 12.4 Theorem Environments which starts with

which means that all these environments are already defined as overlay-specification-aware in beamer. All these environments are like beamerblocks. If you don't want it, use noamsthm as class option in beamerposter:

\documentclass[final,noamsthm]{beamer}

\usepackage[scale=1.24]{beamerposter} % Use the beamerposter package for laying out the poster

\usetheme{confposter} % Use the confposter theme supplied with this template

\newtheorem{theo}{Theorem}

\setbeamercolor{block title}{fg=ngreen,bg=white} % Colors of the block titles
\setbeamercolor{block body}{fg=black,bg=white} % Colors of the body of blocks
\setbeamercolor{block alerted title}{fg=white,bg=dblue!70} % Colors of the highlighted block titles
\setbeamercolor{block alerted body}{fg=black,bg=dblue!10} % Colors of the body of highlighted blocks

\newlength{\sepwid}
\newlength{\onecolwid}
\newlength{\twocolwid}
\newlength{\threecolwid}
\setlength{\paperwidth}{48in} % A0 width: 46.8in
\setlength{\paperheight}{36in} % A0 height: 33.1in
\setlength{\sepwid}{0.024\paperwidth} % Separation width (white space) between columns
\setlength{\onecolwid}{0.22\paperwidth} % Width of one column
\setlength{\twocolwid}{0.464\paperwidth} % Width of two columns
\setlength{\threecolwid}{0.708\paperwidth} % Width of three columns
\setlength{\topmargin}{-0.5in} % Reduce the top margin size

\title{Unnecessarily Complicated Research Title} % Poster title

\author{John Smith, James Smith and Jane Smith} % Author(s)

\institute{Department and University Name} % Institution(s)

\begin{document}

\addtobeamertemplate{block end}{}{\vspace*{2ex}} % White space under blocks

\setlength{\belowcaptionskip}{2ex} % White space under figures
\setlength\belowdisplayshortskip{2ex} % White space under equations

\begin{frame}[t] % The whole poster is enclosed in one beamer frame

\begin{columns}[t] % The whole poster consists of three major columns, the second of which is split into two columns twice - the [t] option aligns each column's content to the top

\begin{column}{\onecolwid} % The first column

\begin{theo}
$\sin^2 x + \cos^2 x = 1$
\end{theo}

\begin{block}{Introduction}
\begin{theo}
Another theorem
\end{theo}
\end{block}

\end{column} % End of the first column

\end{columns} % End of all the columns in the poster

\end{frame} % End of the enclosing frame

\end{document}