LJUBLJANA, YUGOSLAVIA -- An official magazine here has skated out to the thin ice at the edge of socialist Eastern Europe's press censorship laws -- and fallen through.

After a two-week courtroom battle, the radical local weekly Mladina has appeared with a letter from a Georgetown University professor whited out altogether and six black strips over another article.

Mladina's editor admits building the case to test the limits of Yugoslav media openness. The incident also demonstrated, however, that liberalization here already extends beyond the glasnost now celebrated by the official Soviet Bloc press.

"I don't think there's very much you can't do," the editor, Bernard Nezmah, said in an interview, "but I wanted to see for myself."

The Mladina case is the latest in a series of attempts by Ljubljana journals to push Yugoslavia's censorship laws to their outer boundaries.

The media in this liberal city of 300,000 already have surpassed official magazines in neighboring socialist countries, perhaps because Yugoslavia is not a member of the Soviet-led Warsaw Pact and often acts more independently.

Even after it was censored, the current issue of Mladina included items that would be considered taboo in the Soviet Union or other Eastern Bloc countries.

A naked woman is sprawled across the cover, wearing only jewelry. Inside, a joke about former Yugoslav leader Tito is displayed on one page, and a favorable article about a disgraced Yugoslav political figure appears on another.

Two weeks ago, a sharp attack on a prominent Yugoslav party member appeared in Teleks, another local weekly.

In the Soviet Union, criticism of Communist Party officials generally is considered off limits for official newspapers, unless it is launched first by party leaders.

Ljubljana's street kiosks openly display and sell western publications often confiscated as propaganda or pornography by Soviet customs officials, including Playboy, Penthouse and the locally published monthly Erotik.

American news weeklies and West European newspapers and magazines, banned in the Soviet Union and Warsaw Pact countries, also are easily available.

The Ljubljana publications passed a milestone in their liberalization campaign last winter when the official literary monthly Nova Revija, under attack for several controversial positions taken in its February issue, was vindicated by local party officials.

In one article, the journal challenged a movement for greater consolidation of the six Yugoslav republics and called for continued independence for Slovenia, where Ljubljana is located.

The article fed passions about the issue of independence. Slovenia, reputed to be the most independent-minded of the republics, has led a national debate over whether the federal system here should be strengthened or left as it is.

A second article demanded that Yugoslavia's current constitutional review include a discussion of reducing the power of the ruling League of Communists and other moves to increase democratization.

Political leaders in Belgrade, the capital, charged the editors with seeking the secession of Slovenia and demanded that the four-year-old magazine be closed and the editors tried and jailed.

At first, local officials attacked the journal, too. But later they ruled that it had not broken the law and should be allowed to continue publication. The chief editors were replaced, however.

The Mladina case started late last month, when a court ordered an issue of the popular magazine destroyed a day before it was to be released.

One objection was to a letter by Cyril Zebot, a Georgetown professor who allegedly had links with fascist Italy during World War II. Yugoslavia has a strict policy of dishonoring people accused of such connections and his letter was ordered blotted out.

The letter was about a visit that Zebot made to Ljubljana in 1969. "The letter was not at issue," Nezmah said. "What was at issue was the fact that Zebot had written it."

Also censored was a report about an attack on a politician in the local student magazine Katedra.

A judge ordered the Katedra article censored. Nezmah sought to defend Katedra by publishing an article about the case that included quotes from the judge and from the censored article.

In a court hearing, the quotes were ordered cut out of Mladina. The article appeared with black strips over the six sections in question.

"I wanted to show the reader that we still have a little ways to go in media openness," Nezmah said.