1

I am building a presentation using Beamer and the Fitch Natural Deduction package by Selinger.

I am trying to use the \onslide command. For some reason it doesn't work when I follow the syntax and use a parenthesis afterwards {}, but if I just write it as is. Here is a code I found that works:

\documentclass[10pt,pdf]{beamer}

\usepackage{fitch} 
\usepackage{amssymb}

\begin{document}

\begin{frame}
\frametitle {Working}

\[
\begin{nd}
\have {1} {p \rightarrow q} \by {premise} {}
    \open
\onslide<3->    \hypo {2} {\neg q}
        \open
\onslide<5->        \hypo {3} {p} 
\onslide<6->        \have {a} {p \rightarrow q} \r{1}
\onslide<7->        \have {4} {q}   \ie{3,a}
\onslide<8->        \have {5} {q \wedge \neg q} \ai{2,4}
\onslide<9->        \have {6} {\bot} 
        \close
\onslide<4->    \have {8} {\neg p} \ni {3-6}
    \close
\onslide<2-> \have {9} {\neg q \rightarrow \neg p} \pause \ii{2-8}

\end{nd}
\]
\end{frame}


\end{document}

A problem I am facing is the inability to use the \onslide<+->, meaing with the plus sign. Meaning if I change the onslide from 6 onwards - it doesn't show the lines in the order I want to, meaing instead of: \onslide<6-> \have {a} {p \rightarrow q} \r{1}

write this: \onslide<+-> \have {a} {p \rightarrow q} \r{1}

and so on with 7, 8, 9 - when complied the order changes completely.

Thank you for your help.

0

1 Answer 1

1

Note: In your example, I removed the call to \pause (what was it supposed to be used for)?

The <+> notation uses the beamerpauses counter (beamer user guide, p.90). To use this notation from 6th overlays, use \setcounter{beamerpause}{6}.

\documentclass[10pt,pdf]{beamer}
\usepackage{fitch} 
\usepackage{amssymb}
\begin{document}
\begin{frame}
  \frametitle {Working}
  
  \[
    \begin{nd}
      \onslide<1-> \have {1} {p \rightarrow q} \by {premise} {}
      \onslide<1-> \open
      \onslide<3->   \hypo {2} {\neg q}
      \onslide<3->   \open
      \onslide<4->     \hypo {3} {p} 
      \onslide<5->     \have {a} {p \rightarrow q} \r{1}
      \setcounter{beamerpauses}{6}
      \onslide<+->     \have {4} {q}   \ie{3,a}
      \onslide<+->     \have {5} {q \wedge \neg q} \ai{2,4}
      \onslide<+->     \have {6} {\bot} 
      \onslide<+->   \close
      \onslide<4->   \have {8} {\neg p} \ni {3-6}
      \onslide<4-> \close
      \onslide<2-> \have {9} {\neg q \rightarrow \neg p} \ii{2-8}
    \end{nd}
  \]
\end{frame}
\end{document}

enter image description here

2
  • Thank you very much! The \pause command was there because I wanted to justification to appear after another click. Is there an option for that? Also, do you think there is a way line number 7 will appear after line number 3? The line with the \bot.
    – Cantor
    Mar 19 at 15:04
  • @Cantor You can adapt the overlay changes as you wish. Here I just show the use of the beamerpauses counter with +. Mar 19 at 15:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.