Johannes Hudde

Johannes (van Waveren) Hudde (23 April 1628 – 15 April 1704) was a mathematician, burgomaster (mayor) of Amsterdam between 1672 – 1703, and governor of the Dutch East India Company.

Hudde initially studied law at the University of Leiden, until he turned to mathematics under the influence of Frans van Schooten. He contributed to the theory of equations in his posthumous De reductione aequationum of 1713, in which he was the first to take literal coefficients in algebra as indifferently positive or negative. In the Latin translation that Van Schooten made of Descartes' La Géométrie, Hudde, together with Johan de Witt and Hendrik van Heuraet, published work of their own. Hudde's contribution consisted of describing an algorithm for simplifying the calculations necessary to determine a double root to a polynomial equation. And establishing two properties of polynomial roots known as Hudde's rules, that point toward algorithms of calculus.

As a "burgemeester" of Amsterdam he ordered that the city canals should be flushed at high tide and that the polluted water of the town "secreten" should be diverted to pits outside the town instead of into the canals. He also promoted hygiene in and around the town's water supply. "Hudde's stones" were marker stones that were used to mark the summer high water level at several points in the city. They later were the foundation for the "NAP", the now Europe-wide system for measuring water levels.