# Natural Deduction Assistant (NaDeA)

## TL;DR

NaDeA is an online tool based on Isabelle that aids teaching logic through formalized natural deduction, offering formalization results, exercises, and evaluation insights.

## Contribution

This paper introduces NaDeA, a formalized natural deduction assistant in Isabelle, and discusses its educational advantages, formal foundations, and evaluation results.

## Key findings

- NaDeA is effective for teaching logic.
- Formalization in Isabelle enhances reliability.
- Evaluation shows positive educational impact.

## Abstract

We present the Natural Deduction Assistant (NaDeA) and discuss its advantages and disadvantages as a tool for teaching logic. NaDeA is available online and is based on a formalization of natural deduction in the Isabelle proof assistant. We first provide concise formulations of the main formalization results. We then elaborate on the prerequisites for NaDeA, in particular we describe a formalization in Isabelle of "Hilbert's Axioms" that we use as a starting point in our bachelor course on mathematical logic. We discuss a recent evaluation of NaDeA and also give an overview of the exercises in NaDeA.