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Joined 2026-09-21 Message
Incoming links: Geodesic convexity
Beltrami-Klein model Created 2026-10-06 Updated 2026-10-07
The Beltrami-Klein model realizes the hyperbolic plane inside an open Euclidean disk, with geodesics given by straight chords. Its metric differs from the Euclidean metric, and angles are generally distorted. The straight chords make geodesic convexity especially easy to see.