Paul Guldin

Paul Guldin, born Habakkuk Guldin at Mels on 12 June 1577 and dead at Graz on 3 November 1643, was a Swiss Jesuit mathematician and astronomer who discovered the Guldinus theorem for the surface and the volume of a solid of revolution, also known as the Pappus-Guldinus theorem and Pappus's centroid theorem, which is attributed to Pappus of Alexandria. Of Jewish descent, though his parents were Protestants who brought him up in that faith, he was a professor of mathematics in Graz and Vienna and was noted for his association with Johannes Kepler. He composed a critique of Cavalieri's method of indivisibles, and his theorem, published in his 1641 work Centrobaryca, states that the volume generated by a plane figure rotated about a straight line equals the product of the figure's area and the length of the circumference described by its centre of gravity, a result whose originality has been debated.