# How to draw "flag format" lambda derivation diagrams as used in the book Type Theory and Formal Proof: An Introduction

by markeric   Last Updated October 20, 2019 02:23 AM - source

I'd like to draw "flag format" diagrams for lambda derivation as used in the book "Type Theory and Formal Proof: An Introduction". Below is an example in Chapter 2 of the book. How can I do it? Thanks. Tags :

As for all things logical, check the LaTeX for Logicians site, find the thing you need and look up the documentation.

Since you've not given any code, I copied an example from page 3 of flagderiv's documentation.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,amssymb,flagderiv}

\begin{document}

\begin{flagderiv}
\introduce{in-x}{x: \mathbb{N}}{Introduction of $x$}
\assume{as-x}{x > 5}{Assumption}
\step{big-x}{x > 1}{Arithmetic on \ref{in-x} and \ref{as-x}}
\conclude{conc}{x > 5 \implies x > 1}{$\implies$-intro on \ref{as-x} and \ref{big-x}}
\conclude{}{\forall x \in \mathbb{N}: x > 5 \implies x > 1}{$\forall$-intro on \ref{in-x} and \ref{conc}}
\end{flagderiv}

\end{document} 