Ian Stewart*

The catapult that Archimedes built, the gambling-houses that De- scartes frequented in his dissolute youth, the field where Galois fought his duel, the bridge where Hamilton carved quaternions-- not all of these monuments to mathematical history survive today, but the mathematician on vacation can still find many reminders of our subject's glorious and inglorious past: statues, plaques, graves, the card where the famous conjecture was made, the desk where the

famous initials are scratched, birthplaces, houses, memorials. Does your hometown have a mathematical tourist attraction? Have you encountered a mathematical sight on your travels? If so, we invite you to submit to this column a picture, a description of its mathe- matical significance, and either a map or directions so that others may follow in your tracks. Please send all submissions to the Euro- pean Editor, Ian Stewart.

Pavel Samuilovi?: Urysohn F. Palmeira and M. A. Sh ubin

Batz-sur-Mer is a small town by the Atlantic Ocean in northwestern France in the region called Bretagne. To find Batz one proceeds by car or train from Nantes 70 kilometers southwest.

In 1924, the young Russian topologist P. Urysohn drowned in Batz. One can find his grave in the old cemetery (there are two in Batz). The inscription on the tombstone in French reads: Paul Urysohn, mathe- matician, creator of theories of general topology, Pro- fessor at the University in Moscow, born in Odessa on 3 February 1898, drowned while swimming on 17 Au- gust 1924, at 26 years of age, in Batz. The Hebrew in- scription is formed by the first five letters of a religious phrase that can be translated as: "May his soul be bound up in the bond of everlasting life." The Russian

* C o l u m n Editor's address : Mathematics Institute, University of Warwick, Coventry CV4 7AL England.

inscription at the bottom is just his full name: "Pavel Samuilovi~ Urysohn."

Urysohn's name is familiar to anyone who has taken a course in general topology. The following separation theorem is known as Urysohn's Lemma: Given two disjoint closed sets in a normal (T4) topological space, there exists a continuous real-valued function that is 0 on one of the sets and 1 on the other.

Urysohn's grave is easy to find. Turn right at the entrance of the cemetery and follow the wail. Turn left at the corner, keep following the wall, and you will find the grave on your right. Notice how well kept it is from the picture taken by M. A. Shubin.

F. Palmeira Department of Mathematics Pontificia Universidade Cat6lica

do Rio de Janeiro Rio de Janeiro, Brasil

M. A. Shubin Department of Mathematics

and Mechanics Moscow State University Moscow, USSR

THE MATHEMATICAL INTELLIGENCER VOL. 12, NO. 4 ,v~ 1990 Springer-Verlag Ne~ h ork 39