High Quality Content by WIKIPEDIA articles! Yuktibha?a (Malayalam: ?????????; "Rationale in the Malayalam language") also known as Ga?itanyayasa?graha ("Compendium of astronomical rationale"), is a major treatise on mathematics and astronomy, written by Indian astronomer Jyesthadeva of the Kerala school of mathematics in about AD 1530. The treatise is a consolidation of the discoveries by Madhava of Sangamagrama, Nilakantha Somayaji, Parameswara, Jyeshtadeva, Achyuta Pisharati and other astronomer-mathematicians of the Kerala school. Yuktibhasa is mainly based on Nilakantha's Tantra Samgraha. It is considered an early text on some of the foundations of calculus and predates those of European mathematicians such as James Gregory by over a century. However, the treatise was largely unnoticed beyond Kerala, as the book was written in the local language of Malayalam. However, some have argued that mathematics from Kerala were transmitted to Europe (see Possible transmission of Keralese...