mathlib3

4e3729b8 - feat(geometry/euclidean/basic): intersections of circles (#4088)

feat(geometry/euclidean/basic): intersections of circles (#4088) Add two versions of the statement that two circles in two-dimensional space intersect in at most two points, along with some lemmas involved in the proof (some of which can be interpreted in terms of intersections of circles or spheres and lines).