Try doing some basic maths questions in the Lean Theorem Prover. Functions, real numbers, equivalence relations and groups. Click on README.md and then on "Open in CoCalc with one click".
License: APACHE
/- Copyright (c) 2019 Keeley Hoek. All rights reserved. Released under Apache 2.0 license as described in the file LICENSE. Authors: Keeley Hoek, Floris van Doorn -/ import logic.basic meta def error_msg (s : string) : bool := @undefined_core bool $ s ++ ".decidable not inlined" meta def examine (b : Prop) [decidable b] : bool := b #eval examine $ ff ∧ (error_msg "and") #eval examine $ tt ∨ (error_msg "or")