3

I have a Beamer slide in which I would like to emphasize different things sequentially. Here is my MWE:

\documentclass[t,serif,mathserif,professionalfont]{beamer} % 

\setbeamercovered{invisible}
\setbeamercovered{%
  again covered={\opaqueness<1->{40}}}

\mode<presentation>

\usepackage{amsmath}
\usepackage{amssymb}

\begin{document}

\begin{frame}\frametitle{A Title Here}
    \begin{itemize}[<+>]
    \item A first item describing some things
    \item A second item leading to these equations: \par 
    \begin{center}
    \large \vskip -.6cm
    \begin{align}
        {\color<3>{blue} F_m = F_{m-1} + F_{m-1}, \;\; m \in \mathbb{N}} \tag{Eq 1} \\
        {\color<4>{blue} a^n + b^n = c^n, \;\; n \in \mathbb{N}\; \& \; a,b,c \in \mathbb{Z}} \tag{Eq 2}
    \end{align}
    \end{center}
    \item With $F_0=0$ and $F_1=1$, this is Fibonacci's Sequence.
    \item This is Fermat's last theorem.
\end{itemize}   
\end{frame} 
\end{document}

which creates a single slide with three pages.

I specifically want Eq 1 and then Eq 2 to turn blue when the third and fourth items appear, AND I want Eq 2 to be grayed when the third item appears, and Eq 1 to be grayed when the fourth item appears.

The problem is when Eqs 1 or 2 turn blue, they are still grayed. Is there any way to remove the gray for a single element of this sequence of three slides?

2

If you don't mind to abandon the automatic covering done by itemize, you could do:

\documentclass[t]{beamer}

\usefonttheme[onlymath]{serif}
\usefonttheme{professionalfonts}


\setbeamercovered{invisible}
\setbeamercovered{%
    again covered={\opaqueness<1->{40}}}

\mode<presentation>

\usepackage{amsmath}
\usepackage{amssymb}

\begin{document}

    \begin{frame}\frametitle{A Title Here}
        \begin{itemize}
            \item<1> A first item describing some things
            \item<2-4> A second item leading to these equations:
            \onslide<3-4>{%
            \begin{center}
                \large \vskip -.6cm
                \begin{align}
                {\color<3>{blue}\color<4>{gray}F_m = F_{m-1} + F_{m-1}, \;\; m \in \mathbb{N}} \tag{Eq 1}\\
                {\color<4>{blue}\color<3>{gray} a^n + b^n = c^n, \;\; n \in \mathbb{N}\; \& \; a,b,c \in \mathbb{Z}} \tag{Eq 2}
                \end{align}
            \end{center}
        }
        \item<3-> With $F_0=0$ and $F_1=1$, this is Fibonacci's Sequence.
        \item<4-> This is Fermat's last theorem.
        \end{itemize}   
    \end{frame} 
\end{document}

enter image description here


As you might have noticed I replaced some beamer options with

\usefonttheme[onlymath]{serif}
\usefonttheme{professionalfonts}

as the beamer options are obsolete.

  • This doesn't actually answer the question but (+1) for effort. It is very, very hard to make Beamer do what the OP wants, it seems! You could get closer by changing 5 and 6 to 3 and 4 but the greying out of the equations still wouldn't meet the desiderata. – cfr Aug 25 '16 at 23:07
  • @cfr Thanks for your comment! After reading the question again (and then a few more times, it is quite late here :) I changed the answer a bit. I hope this is closer to what the OP has in mind - however it would have been nice to get some feedback from the OP :( – user36296 Aug 25 '16 at 23:39
  • I think that is closer, yes. At least as I understand it. I can't upvote again, though! – cfr Aug 25 '16 at 23:56

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