Mathlib
Atlas
Geometry
Pathway XVIII
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Affine geometry and simplices
Barycentric coordinates. A simplex is the convex hull of affinely independent points.
01
The simplex
A 2-simplex is a triangle. Every interior point is a unique convex combination of the vertices.
4 min
02
Affine geometry
Forget distances and angles. Parallelism and barycenters remain — affine combinations.
4 min
03
Euclidean simplices
Put the inner product back. A triangle has a circumcircle, an orthocenter, and Pythagoras.
4 min
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