May 5, 1984

Charles T. Manatt, chairman of the Democratic National Committee, today announced his intention to form a ''party unity task force'' to resolve disputes among the three Democratic Presidential candidates. Earlier in the day, Walter F. Mondale, Gary Hart and the Rev. Jesse Jackson all indicated a general willingness to participate in discussions that, according to party leaders, would be designed to prevent damaging public disputes among the candidates and their supporters at the Democratic National Convention in July. Even as Mr. Manatt issued his call for unity, however, the candidates continued to hack at one another in campaign stops in Texas, which holds caucuses Saturday, and in Ohio, which holds an important primary next Tuesday. Response to Disclosure The Manatt proposal came in response to the disclosure that Mr. Mondale, Mr. Jackson and Robert S. Strauss met privately in Dallas on Wednesday night to discuss what Mr. Jackson called ''a conflict resolution apparatus,'' with Mr. Strauss as mediator, to heal the divisions created by the battle for the nomination. An aide said that Mr. Manatt regarded this meeting as a ''trial balloon'' from the Mondale camp. Some party leaders added that Mr. Manatt's prompt response was meant to be a signal that he, not Mr. Strauss, should fill the role of mediator among the candidates.

The Reagan Administration is confident that Jose Napoleon Duarte, the leader of El Salvador's Christian Democrats, will win the presidential runoff election Sunday and is planning to invite him to Washington later this month, State Department officials said today. The object, they said, would be to help gain Congressional passage of additional funds for El Salvador. If Mr. Duarte, who is regarded as a moderate, does win, President Reagan will probably address the nation next week on behalf of the Salvadoran aid, the officials said. Officially, the Administration is neutral between Mr. Duarte and his conservative opponent, Roberto d'Aubuisson, head of the Nationalist Republican Alliance. But privately there is no question that senior officials would much prefer Mr. Duarte to win because of Mr. d'Aubuisson's reported links to right-wing death squads.

Congressional experts on military matters generally said today that President Reagan's latest plan to trim the Pentagon budget did not go far enough. They predicted Congress would make additional cuts as it grappled with reducing the budget deficit in the months ahead. As part of those cuts, many lawmakers now believe Congress could delay, or even kill outright, the costly MX missile. One key supporter of the missile said it could lose by as many as 30 votes when it comes to a vote on the House floor later this month.

Only the purest of the purists are grumbling here this week, disappointed that the 20 horses who will run in the 110th Kentucky Derby Saturday may be a substandard and uninspiring bunch. To everyone else in Louisville, including most of the 130,000 who will actually be at Churchill Downs for the race, the Kentucky Derby has little more to do with good horses than a fraternity beer blast does with the finer points of Greek philosophy. The Derby itself, the one horse race of the year that interests those not partial to the sport, is almost an anticlimax after a week of revelry and civic pride. Derby Week is a nonstop festival that seems to have captured the imagination and the support of an entire city. There is a Great Steamboat Race, a Great Balloon Race, a Chow Wagon Festival, a Blue Grass Picnic and dozens of other functions that receive as much attention on local newscasts as developments in Washington or Beirut.

The way Lorraine Wang recalls it, one day a friend approached her and her husband, An Wang, the chairman of Wang Laboratories, and mentioned that the roof was literally falling in at Boston's main performing arts center. The Wangs were not particularly patrons of the arts, Mrs. Wang said, ''but something had to be done.'' So when her Shanghai-born husband asked her if they should help, she replied, ''Why not?'' And without further discussion he pledged $4 million to save the theater from being closed. This was but one of a series of recent philanthropic actions that have made the 63-year-old Chinese immigrant, who came to the United States in 1945, Boston's current leading benefactor.