What was going on when I was born?

''But sir,'' said the student during a seminar on ethnicity that was unusually lively for a Monday morning class, ''it looks like ethnic lines have eroded in New York. Jews, for example, are more assimilated than ever.'' The professor seemed pleased to be challenged but stuck to the thesis of his lecture. ''The city is more heterogeneous now than ever,'' he said.

The National Science Foundation said today that it would spend $200 million to create supercomputer centers at four of the nation's leading universities. The move is the broadest Federal effort yet to promote research using advanced computer technology. Federal officials said the primary motive for the five-year program was a ''desperate, overwhelming need'' among academics for access to supercomputers that could help solve a wide range of basic research problems. Some also said it constituted an American version of Japan's Super- Speed Project, a joint effort of government and industry to build the next generation of high-speed computers.

The Defense Department's top arms control official said today that it was ''a great mistake'' for the United States to continue honoring past accords with the Soviet Union while Moscow was violating ''quite important provisions'' of those agreements. Testifying before the Senate Foreign Relations Committee, the official, Richard N. Perle, Assistant Secretary of Defense for International Security Policy, said it was time to end the ''double standard'' of having Washington adhere ''to every crossed 't' and dotted 'i' '' while letting the Russians ''think they could play fast and loose with these accords.'' The Soviet Union has denied that it has violated arms accords and has in turn accused the United States of breaking the agreements. Query on 1979 Agreement Mr. Perle made the comments when he was asked by Senator Christopher J. Dodd, Democrat of Connecticut, whether he believed President Reagan should continue to abide by the 1979 strategic arms accord with the Soviet Union, which was never ratified, or should dismantle some older Polaris submarines when the seventh Trident submarine, the Alaska, starts sea trials at the end of the year.

Representative Dan Rostenkowski, the chairman of the House Ways and Means Committee, said last night that the time was ripe politically this year for a complete restructuring of the Federal income tax system, and he urged business leaders not to stand in the way of such legislation. ''We only get a chance at profound reform every decade or so,'' Mr. Rostenkowski said in a speech to the Economic Club of New York at the New York Hilton. President Reagan and his Treasury Secretary, James A. Baker 3d, are behind the idea, Mr. Rostenkowski said, and ''Congressional leaders, while rarely enthusiastic about projects which demand such painful choices, appear ready for, or resigned to, the long march.'' Moreover, he added, ''taxpayers are slowly, but surely, warming up to the rewards of reform, and woe to the politician that disappoints the taxpayer.''

The dollar surged to record highs yesterday, encouraged by Washington's apparent reluctance to intervene in foreign-exchange markets to force the dollar down. Currency traders at their computer screens expressed astonishment as light, nervous trading propelled the dollar to levels never before seen. Many said they had no relevant experience to judge what might happen next. ''We're in uncharted waters, and it's anybody's guess where the dollar is going to stop,'' said Lawrence L. Kreicher, an economist at the Irving Trust Company.

In this gritty city, saddled for two decades with an image of urban blight, a community of artists is emerging. Scores of painters, sculptors and other artists - refugees from the soaring rents, shrinking work space and ego-bruising competition in major art centers like Manhattan - have moved here. They say they have discovered affordable, spacious lofts and a more relaxed life while remaining close to New York. In turn, the growing artist population has given rise to new galleries and invigorated older ones, and they have persuaded a group of Manhattan real-estate developers to convert two empty downtown buildings into apartments for artists.

Barely weeks after Latin America's debt crisis showed signs of easing, financial uncertainty has suddenly reappeared in the region, provoked by the problems that several key governments are facing in putting into effect austerity programs. The abrupt dismissal of Argentina's Economics Minister last Monday revived doubts over that country's ability to honor its agreements with the International Monetary Fund and its main foreign creditors. Just a week earlier, the I.M.F. announced it would withhold financial support for Brazil until that Government promised to battle inflation more effectively. Crucial debt talks between Brazil and commercial banks were then suspended.

American negotiators today failed to win agreement with Japan on ending its barriers against imports of forest products. The talks will resume in mid-March. Progress has also been slow concerning a potentially far larger market - telecommunications - although United States officials suggested that the pace had picked up.

Two recently retired employees of the Bank of Boston are under investigation by a Federal grand jury on suspicion that they may have helped the city's organized crime family launder money through the bank, according to sources familiar with the inquiry. The two former employees, a branch manager and a teller, both worked at the Bank of Boston's branch in the North End, a predominantly Italian- American section of the city. The branch is only three blocks from the headquarters of the Angiulo family, the leading criminal syndicate in Boston, according to the Federal Bureau of Investigation. William L. Brown, the chairman of the Bank of Boston, said last week that the bank might have been ''unwittingly'' used by the Angiulos to launder as much as $2 million. Money laundering is the moving of funds resulting from illegal operations into channels where they cannot be traced. But Mr. Brown insisted there was ''no evidence whatsoever'' that any employee of the bank had ''benefited in any way'' from its dealings with the underworld group.

An article in Business Day yesterday about the Phillips Petroleum Company, quoting Wall Street sources, erroneously reported an effort to join with Carl C. Icahn to buy Phillips. The Pennzoil Company, cited in the article, denied yesterday that it was talking with Mr. Icahn or considering a hostile takeover of Phillips. A corrective article appears today on page D4.

For every Carl Icahn and Phillips Petroleum, there are a Rockcor and an N. Norman Muller. The efforts of huge oil companies such as Phillips to ward off Wall Street virtuosos such as Mr. Icahn have become the staple of the financial pages everywhere. But for every multibillion-dollar takeover fought out at stage center, there are a dozen lesser battles, for control of smaller companies, being waged with equal fervor. Consider Rockcor Inc., of Redmond, Wash., which is fighting a dissident slate of directors led by N. Norman Muller, a New York investor who heads American Investment Partners, a Los Angeles partnership. The Muller group, which holds 15 percent of Rockcor's outstanding shares, is trying to win control of the company at its annual meeting March 19.

TUESDAY, FEBRUARY 26, 1985 International The top weapons control official in the Pentagon, Richard N. Perle, told a Senate hearing it was ''a great mistake'' for the United States to continue honoring weapons control agreements with the Soviet Union while Moscow was violating ''quite important provisions'' of them. Moscow has denied violating arms accords and has in turn accused Washington of breaking the agreements. (Page A1, Column 1.) A spurt in Soviet arms spending has occurred for the first time since the mid-1970s, according to analysts for the C.I.A. and the Pentagon. However, the agencies differed sharply on the pace of the latest buildup and its implications. (A12:1.)