Pierre Hérigone

Pierre Hérigone, in Latin Petrus Herigonius, who lived from 1580 to 1643, was a French mathematician and astronomer of Basque origin who taught in Paris for most of his life. Only one work by him is known to exist, the Cursus mathematicus, nova, brevi, et clara methodo demonstratus, per notas reales et universales, published in Paris in six volumes from 1634 to 1637 with a second edition in 1644, a compendium of elementary mathematics in French and Latin that introduced a system of mathematical and logical notation. Florian Cajori wrote that it shows a full recognition of the importance of notation and an almost reckless eagerness to introduce an exhaustive set of symbols. Hérigone may have been the first to introduce a symbol for an angle, recorded the use of the less-than sign and introduced the upside-down T for perpendicularity.