CAVALIERI

Bonaventura Cavalieri, Italian mathematician belonging to the order of the Jesuits, considered one of the precursors of modern infinitesimal calculus. He was the first to introduce in Italy the logarithmic calculus, but owes his celebrity to his theory of the "indivisible", which he exposed in Geometria indivisibilibus continuorum quadam nova ratione promota. This theory studies geometric magnitudes as composed of an infinite number of elements, or indivisible, which are the last terms of decomposition that can be done. The measurement of the lengths, of the surfaces and of the volumes becomes to make the sum of the infinity of indivisible: it is the principle of the calculation of a definite integral, although without the modern rigorous notion of passage to the limit. This is why it can be considered as one of the precursors of modern infinitesimal analysis. Cavalieri’s Principle is based on this theory.