How to reach Yuri Matiyasevich:

Permanent coordinates
(in St.Petersburg, Russia) :
e-mail: yumat@pdmi.ras.ru
phone: 7 (812) 528 47 68 (home)
7 (812) 571 43 92 (office)
7 (812) 312 40 58 (secretary of my Institute;
does not speak English!)
fax:  7 (812) 310 53 77  (at my Institute)
mailing 
address: 
27, Fontanka
Steklov Institute of Mathematics (POMI)
St.Petersburg RUSSIA 191023 

URL of my original Home page is http://logic.pdmi.ras.ru/~yumat/index.html.
It has a mirror at http://www.informatik.uni-stuttgart.de/ifi/ti/personen/Matiyasevich/index.html.
All comments can be e-mailed to me, Yuri Matiyasevich.