Call it breaking the ice, or as some officials of the host nation are saying, a "good sign" for the 1988 Summer Olympics in Seoul: top Soviet figure skaters arriving in South Korea today and set to perform there beginning Friday on the first visit by U.S.S.R. athletes to that nation since 1945.

It's part of an international exhibition tour that includes 12 Soviet skaters and eight from communist Czechoslovakia and East Germany (including world champion Katarina Witt), the United States' Tiffany Chin and other stars of the recent World Championships in Tokyo. And it marks the Soviet Union's first cultural visit to the nation since the shooting down of a Korean Air Lines jet in 1983.

"Soviet officials have shown a friendly attitude during contacts with South Korean skating officials since 1982," Lee Soo-Young, president of the Korean Amateur Skating Association said . . .

The United States Olympic Committee, seeking to broaden its sources of income and at the same time keep the Olympic image prominent during off years, announced an agreement with three companies (Howard/Marlboro Group, Hamilton Projects Inc., Ohlmeyer Communications) to develop programs in the key areas of television, licensing and marketing . . .

The Los Angeles Olympic Organizing Committee announced its first project to be paid for from the enormous surplus generated from the 1984 Summer Olympics, a $2 million program to expand operating hours and supervision at southern California parks and recreation centers. It will be called Summer Games '85, climaxing in an Olympic-style meet.