Unfortunately, beamer
doesn't offer part navigation bars out of the box, however you can create the necessary commands \insertpartnavigation
and \insertpartnavigationhorizontal
yourself:
\documentclass{beamer}
\usetheme{Warsaw}
\usecolortheme{spruce}
%%% Part navigation (http://tex.stackexchange.com/a/103431) %%%
% The templates "part in head/foot" and "part in head/foot shaded" control the appearance of the part navigation
\defbeamertemplate*{part in head/foot}{default}
{\insertparthead\hfil}
\defbeamertemplate*{part in head/foot shaded}{default}[1][50]
{\color{fg!#1!bg}\usebeamertemplate{part in head/foot}}
\setbeamercolor{part in head/foot}{parent=section in head/foot,fg=red}
\makeatletter
\def\insertpartnavigation#1{%
\ifnum\c@part>0
\hbox to #1{%
\vbox{{\usebeamerfont{section in head/foot}\usebeamercolor[fg]{part in head/foot}%
\vskip0.5625ex%
\def\slideentry##1##2##3##4##5##6{}%
\def\sectionentry##1##2##3##4##5{}%
\def\partentry##1##2{
\def\insertparthead{##1}
\def\insertpartheadnumber{##2}%
\setbox\beamer@tempbox=\hbox{%
\hyperlink{Outline##2}{\hbox to #1{%
\hskip0.3cm%
\ifnum\c@part=##2%
{\usebeamertemplate{part in head/foot}}%
\else%
{\usebeamertemplate{part in head/foot shaded}}%
\fi\hskip0.3cm}}}%
\ht\beamer@tempbox=1.6875ex\dp\beamer@tempbox=0.75ex%
\box\beamer@tempbox}%
\dohead\vskip0.5625ex}}\hfil}\fi}
\def\insertpartnavigationhorizontal#1#2#3{%
\ifnum\c@part>0
\hbox to #1{{%
\def\slideentry##1##2##3##4##5##6{}%
\def\sectionentry##1##2##3##4##5{}%
\def\partentry##1##2{% part title, part numer
\hskip1.875ex plus 1fill
\hbox{\def\insertparthead{##1}%
\def\insertpartheadnumber{##2}%
{%
\usebeamerfont{part in head/foot}\usebeamercolor[fg]{part in head/foot}%
\ifnum\c@part=##2%
\hyperlink{Outline##2}{{\usebeamertemplate{part in head/foot}}}%
\else%
\hyperlink{Outline##2}{{\usebeamertemplate{part in head/foot shaded}}}%
\fi}%
}%
\ignorespaces}
#2%
\usebeamerfont{part in head/foot}\usebeamercolor[fg]{part in head/foot}%
\hskip-1.875ex plus-1fill\dohead%
\hfil%
#3}}\fi}
% Headline with part navigation
\setbeamertemplate{headline}
{%
\leavevmode%
\@tempdimb=2.4375ex%
\ifnum\beamer@subsectionmax<\beamer@sectionmax%
\multiply\@tempdimb by\beamer@sectionmax%
\else%
\multiply\@tempdimb by\beamer@subsectionmax%
\fi%
\ifdim\@tempdimb>0pt%
\advance\@tempdimb by 1.825ex%
\begin{beamercolorbox}[wd=.5\paperwidth,ht=\@tempdimb]{section in head/foot}%
\vbox to\@tempdimb{\vfil\insertpartnavigation{.25\paperwidth}\vfil}%
\vbox to\@tempdimb{\vfil\insertsectionnavigation{.25\paperwidth}\vfil}%
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.5\paperwidth,ht=\@tempdimb]{subsection in head/foot}%
\vbox to\@tempdimb{\vfil\insertsubsectionnavigation{.5\paperwidth}\vfil}%
\end{beamercolorbox}%
\fi%
}
% Footline with part navigation
\setbeamertemplate{footline}
{%
\leavevmode%
\hbox{%
\begin{beamercolorbox}[wd=.5\paperwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,rightskip=.3cm]{author in head/foot}%
\insertpartnavigationhorizontal{.3\paperwidth}{}{\hskip0pt plus1filll}\hfill\usebeamerfont{author in head/foot}\insertshortauthor
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.5\paperwidth,ht=2.5ex,dp=1.125ex,leftskip=.3cm,rightskip=.3cm plus1fil]{title in head/foot}%
\usebeamerfont{title in head/foot}\insertshorttitle
\end{beamercolorbox}}%
\vskip0pt%
}
\makeatother
%%% End of code for part navigation %%%
\title{Example Beamer}
\subtitle{Sub Title}
\author{Ray J. Stomach}
\AtBeginPart{
\begin{frame}
\partpage
\end{frame}
}
\AtBeginSection{
\begin{frame}
\tableofcontents[currentsection]
\end{frame}
}
\newcommand\testsubsection[1]{
\subsection{#1}
\begin{frame}
\begin{itemize}
\item A black cat
\item jumps over a big
\item a blat fox
\end{itemize}
\end{frame}
}
\begin{document}
\frame{\maketitle}
\part{Part 1}
\section{Section 1}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\section{Section 2}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\section{Section 3}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\part{Part 2}
\section{Section 1}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\section{Section 2}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\section{Section 3}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\part{Part 3}
\section{Section 1}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\section{Section 2}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\section{Section 3}
\testsubsection{Subsection A}
\testsubsection{Subsection B}
\testsubsection{Subsection C}
\end{document}

Of course, you don't need a part navigation in both the head- and footline, you can simply delete either the redefinition \setbeamertemplate{headline}{...}
or \setbeamertemplate{footline}{...}
to remove the superfluous one. Or you can create your own one using the newly introduced macros \insertpartnavigation
and \insertpartnavigationhorizontal
- they are used exactly like the corresponding commands \insertsectionnavigation(horizontal)
, cf. the beamer
user guide, p. 64.
The appearance of the part navigation is controlled by the templates part in head/foot
and part in head/foot shaded
, so you can e.g. change its color by issuing something like \setbeamercolor{part in head/foot}{fg=white}
.
After a small correction of (first version of) your code:
\documentclass{beamer}
\usetheme{Ilmenau}
\usecolortheme{beaver}
\begin{document}
\begin{equation}
1+1=2
\end{equation}
\begin{equation}
1+1=2 \tag{mytag}
\end{equation}
\end{document}

The source of your problem seems to be inline formula, i.e. between dollar signs, not inside, say, equation
environment.
Best Answer
You can try the following commands:
An example that I took from Wikibooks:
Their result:
Don't forget to add
at the beginning of your document