December 3, 1984

A 23-year-old Harvard graduate who came to New York City this fall to study acting was forced at knifepoint to the roof of her Upper West Side apartment building early yesterday and stabbed to death when she resisted being raped, the police said. The victim, Caroline Isenberg, died on an operating table at St. Luke's Hospital at 7:30 A.M., six hours after being stabbed repeatedly in the chest on the darkened roof of her seven-story building at 929 West End Avenue, between 105th and 106th Streets. Before she died, Miss Isenberg, who was said to be lucid and eager to talk despite her wounds, provided the police with an account of the assault. The killer escaped over the roof of an adjacent building as police officers summoned by neighbors raced to the scene. ''There was a hell of a struggle up there,'' said Noreen Williams, a sixth- floor resident, who heard the victim's screams from the roof at 1:30 A.M. and called the police. ''I heard the whole thing, but there was nothing I could do about it. There was nothing anybody could do about it.

Although the profound changes in tax policy proposed by the Treasury last week would eliminate major breaks for business, no single wave of opposition has yet to emerge from the corporate world. In fact, some corporations, at least in public, are putting in a good word for the principle of tax simplification and a more equitable system even as they complain about provisions that would hurt their industry. Not all industries would suffer equally under the changes. Basic industries might find capital formation more difficult, business people say, but service industries might benefit. Specifically, the Treasury's proposal would eliminate the investment tax credit, curb accelerated depreciation schedules and end much of the preferential treatment of capital gains. Some executives see these and other provisions as disruptive to the economy. But the plan would also lower the basic corporate tax rate to 33 percent, from 46 percent, a change that elicited some support.

For the second time in two years, Davvid H. Hoag, the new chief executive of the LTV Steel Company, has unexpectedly moved up to the No. 1 spot at a company. And for the second time in a row, the 45-year-old Pittsburgh native takes the helm when his company is mired in hard times. In April 1983, Thomas C. Graham suddenly resigned as chief executive or the Jones & Laughlin Steel Corporation, a subsidiary of the Dallas-based LTV Corporation, nd Mr. Hoag was called on to fill the top spot. That move came at what was probably the steel industry's bleakest time since the Depression. And l ast Thursday, E. Bradley Jones, chairman and chief executive last June 28 when Jones & Laughlin merged with the Republic Steel Corporation - resigned unexpectedly, and Mr. Hoag has again taken the helm. This time, he takes over not only when much of the arduous job of merging the two steel behemoths remains undone but also when the industry is staggering from a plunge in demand and prices.

The Senate's new Republican leaders gave their first estimates today of how much they think President Reagan should slow the growth of military spending to help reduce Federal budget deficits. The leaders insisted that cuts in growth would have to be made, despite the White House contention that such restraint might compromise arms control talks with the Soviet Union set to start in January. First Indication of Magnitude Republican Congressional leaders have previously told the President that the military budget should be included in any package of spending reductions he proposes to Congress, but the comments made today were the first indication of the amount of restraint the leaders want to see in the military budget. Bob Dole of Kansas, the new Senate majority leader, suggested reductions in projected military budgets totaling $30 billion to $50 billion over the next three years. He said reductions of that magnitude should be part of an overall $200 billion deficit reduction package designed to bring the deficit well under $100 billion by the fiscal year 1988. The deficit is projected at about $210 billion this year.

The day of John Michael Paddack's first celebration of mass was a gift of cold winter sunshine. The Lord, said Father Paddack, had blessed this day with His strong hand and with His gentle hand - the bite of winter and the warmth of the sun. ''I looked in the mirror this morning and I didn't see any physical change, but I felt a confidence and a sense of happiness that I had never felt before,'' said Father Paddack, one of 17 priests who had been ordained Saturday at St. Patrick's Cathedral in Manhattan. ''I knew that God had affirmed my decision.'' The group, from St. Joseph's Seminary at Dunwoodie in Yonkers, was the largest to enter the priesthood in New York since 1971. Saturday had been a glorious ceremony for them, an emotional linking of 17 men to generations of priests who had served the church. John Paddack had walked beneath the vaulted arches of the cathedral, laid his body on the altar and committed his life to God.