May 9, 1984

''In these conditions, the National Olympic Committee of the U.S.S.R. is compelled to declare that participation of Soviet sportsmen in the Games of the XXIII Olympiad in Los Angeles is impossible.

Soviet athletes will not compete in the Olympic Games in Los Angeles this summer, Moscow announced. It attributed the decision to a ''gross flouting'' of Olympic ideals by United States officials. In particular, the statement cited plans by anti-Soviet groups to hold demonstrations during the Games and a United States refusal to prohibit such protests. (Page A1, Columns 4-6.) The Soviet decision not to attend the Summer Olympics in Los Angeles was deplored by the Reagan Administration as ''a blatant political action for which there was no real justification.'' Administration specialists on the Soviet Union said they believed that Moscow's action was at least partly in retaliation for the American boycott of the Moscow Summer Games in 1980. (A16:1-4.)

My heart is inditing a good matter; my tongue is the pen of a ready writer.'' The unveiling of those lines from the King James Version of the 45th Psalm, inscribed in stone and raised in song, marked the climax Monday night to the dedication of an American Poets' Corner at the Cathedral of St. John the Divine. Several hundred congregants and guests gathered in the cathedral at Amsterdam Avenue and 112th Street, itself a poem of stone arches and stained glass, to honor the written word, particularly as put down by Emily Dickinson, Walt Whitman and Washington Irving. Outsized candles flickered gamely under floodlights, as sacred music, high language and church ceremony heralded the birth of a tradition.

PASTA is one of the most versatile foods there is, but when you do the things they do. . . .'' Alfredo Viazzi paused for a sigh and a lift of his well-defined eyebrows. ''Cold tortellini salad with pesto,'' he said somewhat sadly, ''it's an outrageous thing.'' Mr. Viazzi is a Greenwich Village restaurateur who has been serving Italian food to New Yorkers for the last 30 years. (He owns Cafe Domel, Trattoria da Alfredo and Tavola Calda da Alfredo.) He is one of several Italian chefs who were interviewed recently about pasta, in particular the variations on pasta that are being offered, and apparently consumed, with enthusiasm these days: colored and flavored pasta, cold pasta salads, pasta in strange and, to Italians, unwieldy combinations. Tortellini, for example, the little doughnut-shaped, meat-filled Bolognese specialty, is now often served cold with pesto, a pungent basil and garlic sauce that is closely identified with Genoa. ''The pesto sauce doesn't match the pasta,'' said Giuliano Bugialli. ''It fights with the pasta.'' Mr. Bugialli, an authority on Recipes are on page C6. the history of Italian food, is a cookbook writer who conducts cooking classes in this country and, in the summer and fall, in his native Florence.

Because of an editing error, a Man in the News article yesterday on Jose Napoleon Duarte, who has claimed victory in the Salvadoran election, misinterpreted a reference to ''leftist idealists'' whom he wants to include in a national dialogue. His reference was to unarmed leftists, mainly those of the Revolutionary Democratic Front.