Date: Wed, 1 Feb 1995 20:32:38 -0500 From: [Permission pending] To: rusin@math.niu.edu Subject: Re: Bezout's Theorem Thanks for your comment on my Bezout post. I should have said Bezout's Lemma in the first place or maybe Bezout's Identity. Both of which I have actually seen in print. As several responders mentioned, Bezout's Theorem is a well-known result in algebraic geometry, namely, ``If two projective curves C and D in P_2 of degrees m and n have no common component, then they have precisely mn points of intersection counting multiplicities.'' However Dipankar wrote: See, for example, Kirwan ``Complex Algebraic Curves'' LMSST #23, Cambridge (chap 3). Kirwan notes that the reason for associating B{\'e}zout's name to the theorem ``is not entirely clear, since although B{\'e}zout gave a proof of the theorem, it was neither correct nor the first proof to be given''. The following is another response of some interest. At least it tells something about Bezout: I have read in some place, that in fact, the lemma you mention, has been brought to the attention of mathematicians by " Bachet de Meziriac" contemporary of Fermat, Pascal.... and known above all by his book "Problemes plaisans (sic) et delectables", title easy to translate. That book is a collection of nice problems in arithmetic, wri tten for amusement. In that time, there was no TV... Perhaps, B d M has learnt the lemma from Diophante (?). But, by tradition, the lemma in question is said "de Bezout". Bezout, French mathematician lived during the 19th century. Fans of the history of mathematics may give more informations.... -- ******************************************************************** * Yvon SIRET * * 38041 Grenoble cedex 9 - France * * Tel: (33) 76-54-03-62 Fax: (33) 76-42-11-71 * * Internet: Yvon.Siret@grenet.fr * ******************************************************************** I also found reference in at least one place to the fact that an integral domain in which every finitely generated ideal is principle is called a Bezout ring. [sig deleted]