[{"data":1,"prerenderedAt":4},["ShallowReactive",2],{"ZcMytJNBhF":3},"# Straightedge and compass construction in Lean\n\n[![Documentation](https://img.shields.io/badge/Documentation-passing-green)](https://wwylele.github.io/Compass/docs/)\n\nThis project formalizes some basic theory of [straightedge and compass construction](https://en.wikipedia.org/wiki/Straightedge_and_compass_construction) in Lean,\nincluding a prove of theorem #8 from Freek Wiedijk's list of 100 theorems.\n\n## Main declarations\n\n- `EuclideanGeometry.ConstructiblePoint`: predicate for constructible points using straightedge and compass.\n- `constructibleClosure`: constructible closure of a field. That is, the union of all iterated quadratic extensions of th field.\n- `EuclideanGeometry.ConstructiblePoint.mem_constructibleClosure`: constructible points on the complex plane are in the constructible closure.\n- `EuclideanGeometry.constructiblePoint_of_mem_constructibleClosure`: constructible numbers are all constructible points\n- `EuclideanGeometry.not_exist_angle_trisection`: the impossibility of trisecting the angle.\n- `EuclideanGeometry.not_exist_doubling_cube`: the impossibility of doubling the cube.",1787169617400]