headline with Madrid beamer presentation theme

Question

I using the following codes

  \documentclass{beamer}
   \usepackage[T1]{fontenc}
   %-----
   \usepackage{amsmath,amssymb,amsfonts} %math
   \usepackage{graphicx}
   \usepackage{color} 
    \usetheme{AnnArbor}

   \begin{document}
    \section{section1}
   \subsection{subsection1}
   \begin{frame}{}

    A. Rhandi , G. R. Goldstein and J. A. Goldstein (2011) have proved a new 
    results of this type replacing \alert{$\Delta$} by the Kolmogorov 
    operator in $L^2(\mathbb{R}^N,\alert{\rho(x)dx})$:
    \end{frame}

    \subsection{subsection2}
    \begin{frame}{}

    \end{frame}

     \end{document} 

My goal is to get a headline like this with the theme Madrid :

Thank you!

Answer 1

You can enable this headline with the optional argument secheader of the Madrid theme.

Please note that you need neither \usepackage{graphicx} nor \usepackage{color} with beamer.

\documentclass{beamer}
\usepackage[T1]{fontenc}

\usepackage{amsmath,amssymb,amsfonts} %math

\usetheme[secheader]{Madrid}


\begin{document}
\section{section1}
\subsection{subsection1}
\begin{frame}{}
A. Rhandi , G. R. Goldstein and J. A. Goldstein (2011) have proved a new 
results of this type replacing \alert{$\Delta$} by the Kolmogorov 
operator in $L^2(\mathbb{R}^N,\alert{\rho(x)dx})$:
\end{frame}

\subsection{subsection2}
\begin{frame}{}

\end{frame}

\end{document}