Rising labor tensions challenge Sweden's new prime minister. Since Prime Minister Palme's assassination seven months ago, Sweden has been in a state of limbo. Now, rising domestic pressures are likely to point up just how much Sweden could change under Palme's successor, Ingvar Carlsson.

A wreath of red roses lies on the spot where Prime Minister Olaf Palme was gunned down after he and his wife left a Stockholm cinema on the night of Feb. 28. Otherwise, the street is empty -- an image that mirrors the results of investigations of the assasination. They are completely bereft of clear clues as to who was behind the killing seven months ago.

``You would have thought by now the police would have dusted off all the old files, and gone through all the evangelicals, the Nazis, the Middle East groups, and come up with something. But there's nothing,'' says one journalist.

For a country that had not had a political murder in nearly 200 years, the assassination stunned Sweden, which suddenly felt it had lost its innocence. But the Swedes' trauma was short-lived, says Nordal Akerman, managing director of the Swedish Institute of International Affairs.

``For a few days they were absolutely stunned,'' says Dr. Akerman. ``It couldn't happen here, they said. Sweden's not invulnerable any more. One week later and they thought the invulnerability was just an exception.''

Akerman, who knew Palme well and describes him as having had ``a rather cold personality,'' says Swedes ``didn't mourn Olaf Palme as much as the attack on the sanctity of Swedish democracy.''

But, without Sweden's most powerful figure, the country has been in a state of limbo, making it unclear how much Sweden may change under Palme's successor, Ingvar Carlsson.

Certainly no major shifts in policy are likely. Although always in the background, Carlsson was a key figure in the Social Democratic Party -- acting as Palme's No. 2, as his party's trouble shooter on major sensitive issues, and as an influencer of party policy.

Talks with numerous politicians confirm a view of Palme as a man of remarkable political gifts who was also arrogant, petty, and vindictive. By comparison, Carlsson is seen as quiet, even dull.

A former cabinet minister says two things distinguished the two men. First, while Palme was apt to be a demagogue, determined to win his argument, Carlsson is more likely to be a conciliator. Second, Carlsson, who has solid working-class roots compared to Palme's patrician background, is considered more of a true Social Democrat. Ideologically he is more dogmatic.

Commentators expect more noticable differences between the two men to emerge in the arena of international affairs.

Palme thrived in the international circuit, and was adored in third-world circles. But his involvement in foreign affairs sometimes cost him dearly at home.

Palme's support for third-world causes, and his harsh criticism of the morality of the Vietnam War, led one observer to tartly suggest that ``Sweden's greatest export is unsolicited advice.''

Analysts do not expect Carlsson to be as combative as Palme in conducting foreign policy, nor that he will project Sweden as much onto the center stage of international affairs.

Moreover, domestic pressures seem sure to command Carlsson's full attention. Despite the fact that a threatened public sector strike was called off Tuesday, Carlsson still faces challenges on the labor front.

Although a deal worked out in April with private-sector workers applies through 1987, the agreement cannot be divorced from a likely strike in the public sector. The private-sector agreement is conditional on inflation staying below 3.6 percent. A costly settlement of any public-sector strike would drive up inflation and almost certainly unravel the April's private-sector agreement, causing turmoil on the labor scene.

Bo Ekegren, editor of a magazine of Swedish Employers Confederation, foresees an ``unsolvable situation with very militant unions in the public sector, and more and more people tired of paying more and more taxes.''

Mr. Ekegren believes the government must be very firm with public-sector unions ``so there will not be unrest in the private sector. This is a very crucial and dangerous situation,'' he says.

But labor, on the other hand, complains that inequities in the current distribution of wealth -- almost a contradiction of terms in Sweden -- show a new and unacceptable face of Swedish society.

Anna Hedborg, an economist with the blue-collar Swedish Trade Union Confederation, points to the ability of ``bright, young people'' to make vast sums of money speculating on the Stockholm stock exchange.

``We don't like this,'' she says. ``For the first time since the 1980s we see a new exclusiveness coming up.''

At the same time, what Dr. Akerman of the Swedish Institute for International Affairs refers to the ``discontent of rising expectations,'' which is causing strife within the union movement between both blue- and white-collar workers and private- and public-sector employees. He believes a philosophical change has taken place in egalitarian Sweden.

``There is less striving for equality. There is now more jealousy,'' he says.

The most significant development on the labor market, he points out, is the rapid expansion of the public sector in the last 20 years. More than 60 percent of all wage earners are employed in the public sector. This, he says, is due to:

The traditional need in Sweden to maintain high employment.

The demand for more public services.

Despite its more powerful role in Sweden's welfare state, the public sector argues that it lags behind the private sector in its wage differentials. Hence the call for Tuesday's strike.

But this only adds to the financial problems of a country where more and more people feel burdened by taxes in what is the most highly taxed country in the world. On average, 50 percent of a Swede's paycheck goes toward taxes.

All of this adds up to a critical test both for Prime Minister Carlsson and for the ``Swedish model,'' an international byword for sound labor relations.

Harmony is becoming increasingly difficult to achieve, not just between employers and unions, but within the different unions themselves.