Map · 51
geometry
MSC 51 · Geometry
3,805 declarations (3,344 theorems, 461 definitions) across 76 files. 8 of the 99 famous theorems listed for this area are in Mathlib (8%), 9 in some Lean library. 31 open conjectures here are stated in Lean.
Files are assigned to areas by a language model reading each file's documentation. Report a file that is in the wrong area.
Subareas5
- 51M Real and complex geometry 2,279
- 51A Linear incidence geometry 1,087
- 51N Analytic and descriptive geometry 229
- 51K Distance geometry 200
- 51E Finite geometry and special incidence structures 10
Famous theorems8 of 99
From the 1000+ theorems project, which classifies each theorem by MSC area.
Not yet in Mathlib · 91
In Mathlib · 8
- Commandino's theoremAffine.Simplex.point_vsub_centroid_eq_smul_vsub
- Exterior angle theoremEuclideanGeometry.exterior_angle_eq_angle_add_angle
- Heine–Cantor theoremCompactSpace.uniformContinuous_of_continuous
- Ptolemy's theoremEuclideanGeometry.mul_dist_add_mul_dist_eq_mul_dist_of_cospherical
- Pythagorean theoremEuclideanGeometry.dist_sq_eq_dist_sq_add_dist_sq_iff_angle_eq_pi_div_two
- Tangent-secant theoremEuclideanGeometry.Sphere.dist_sq_eq_mul_dist_of_tangent_and_secant
- Thales's theoremEuclideanGeometry.Sphere.thales_theorem
From the 100 theorems list7
Open conjectures stated in Lean31
Statements without proofs, collected by the Formal Conjectures project.
- Erdos1082.erdos_1082.parts.iErdős Problems
- Erdos1088.erdos_1088Erdős Problems
- Erdos160.erdos_160.better_lowerErdős Problems
- Erdos160.erdos_160.better_upperErdős Problems
- Erdos189.erdos_189.variants.parallelogramErdős Problems
- Erdos352.erdos_352Erdős Problems
- Erdos503.erdos_503Erdős Problems
- Erdos506.erdos_506Erdős Problems
- Erdos506.erdos_506.variants.small_nErdős Problems
- Erdos507.erdos_507.equivalentErdős Problems
- Erdos507.erdos_507.lowerErdős Problems
Undergraduate topics still missing15 of 29
From Mathlib's own undergraduate checklist.
Affine and Euclidean Geometry · 15 of 29
- General definitions › equations of affine subspace
- General definitions › affine property
- General definitions › group generated by homotheties and translations
- General definitions › transformations fixing a basis of directions
- Euclidean affine spaces › isometries that do and do not preserve orientation
- Euclidean affine spaces › direct and opposite similarities of the plane
- Euclidean affine spaces › classification of isometries in two and three dimensions
- Euclidean affine spaces › angles between planes
- Euclidean affine spaces › group of isometries stabilizing a subset of the plane or of space
- Euclidean affine spaces › regular polygons
- Euclidean affine spaces › metric relations in the triangle
- Euclidean affine spaces › using complex numbers in plane geometry
- Application of quadratic forms to study proper conic sections of the affine Euclidean plane › focus
- Application of quadratic forms to study proper conic sections of the affine Euclidean plane › eccentricity
- Application of quadratic forms to study proper conic sections of the affine Euclidean plane › quadric surfaces in 3-dimensional Euclidean affine spaces
Files76
Largest first. The code after each file is its assigned subarea.
- Mathlib.Analysis.Normed.Affine.Isometry
Affine isometries
51K · 200
- Mathlib.Geometry.Euclidean.Incenter
Incenters and excenters of simplices.
51M · 182
- Mathlib.LinearAlgebra.AffineSpace.AffineEquiv
Affine equivalences
51A · 170
- Mathlib.LinearAlgebra.AffineSpace.AffineMap
Affine maps
51A · 170
51A · 165
- Mathlib.Analysis.Convex.Side
Sides of affine subspaces
51M · 156
51A · 146
- Mathlib.Topology.Algebra.ContinuousAffineMap
Continuous affine maps.
51N · 124
- Mathlib.Geometry.Euclidean.Angle.Oriented.Basic
Oriented angles.
51M · 123
- Mathlib.Geometry.Euclidean.Angle.Oriented.Affine
Oriented angles.
51M · 116
- Mathlib.LinearAlgebra.AffineSpace.Simplex.Basic
Simplex in affine space
51A · 109
- Mathlib.Topology.Algebra.ContinuousAffineEquiv
Continuous affine equivalences
51N · 105