Original: The theorems of Alhacen , Khayyam and al-Tusi on quadrilaterals , including the Ibn al-Haytham â '' Lambert quadrilateral and Khayyamâ '' Saccheri quadrilateral , were the first theorems on hyperbolic geometry .
Simplified: The theorems of Alhacen , Khayyam on quadrilaterals , were the first theorems on hyperbolic geometry .