Letter (reply to the letter of 16.07.1979) writes about invitation for Dr. Slisenko and his hope to raise the quota for soviet participants; asks not to refuse to attend the symposium Date: 27.07.1979 Original document language: russian Authors: Andrei Petrovich Ershov Persons: Anatol O. Slisenko, Vladimir A. Uspensky Addressee: Nikolai A. Shanin