In mathematics, the Hadwiger–Finsler inequality is a result on the geometry of triangles in the Euclidean plane, named after the mathematicians Hugo Hadwiger and Paul Finsler. It states that if a triangle in the plane has side lengths a, b and c and area T, then
- Finsler, Paul; Hadwiger, Hugo (1937). "Einige Relationen im Dreieck". Commentarii Mathematici Helvetici 10 (1): 316–326. doi:10.1007/BF01214300.