June 15, 1981

The Koch administration has decided to seek a cut in taxes on commercial banks despite some internal opposition, and is expected to reach agreement with the state on specific legislation later this week. The opposition came from the city's Commissioner of Finance, Philip R. Michael, who said the move could cost the city millions in lost tax revenues. Mr. Michael, a mayoral appointee, made his objections known in a confidential memorandum to Mayor Koch. In that three-page memorandum, dated May 18, he argued that reducing the taxes on commercial banks would not only hurt the city financially, but would also fail to keep banks in New York, the main goal of those pushing for such a cut. Reducing the taxes would make New York more competitive with other parts of the nation, proponents of the idea maintain.

A tentative proposal to build a 25-story building on upper Fifth Avenue next to the turn-of-the century mansion that now houses the Jewish Museum is causing concern in the neighborhood and a renewal of efforts to have the mansion given landmark status. The Jewish Theological Seminary of America, which owns the museum and the land at the northeast corner of Fifth Avenue and 92d Street, says the museum needs more space for its exhibits and additional revenue for its upkeep. The proposed building, according to a spokesman for the seminary, is only one of the options under consideration. The seminary emphasizes that there are no plans to alter or destroy the former Felix M. Warburg mansion, which was built for the banker in 1907. It also asserts that one of the options being considered is just to leave the site as it is and find other ways to raise the necessary funds.

Despite the big movie and paperback deals that convey an impression of glamour and prosperity, the average author in the United States doesn't live on Easy Street. He or she earns less than $5,000 a year from writing, and has to make ends meet with the help of other jobs - or a working spouse. These are among the results reported in a major pioneering study to be issued today by Columbia University's Center for the Social Sciences about the economics, and frustrations, of professional authors in this country. ''On the average,'' the social scientists say, ''writing yields little economic return.'' Based on responses from 2,239 authors producing books in every field of fact and fiction, who were pledged anonymity, ''The Columbia University Survey of American Authors'' is a 150-page document that is the most detailed account ever made of how writers earn a living, or don't, and yet survive. For analytical purposes, an author was defined as a contemporary American writer who had had at least one book published. The Happy Minority While generally gloomy, the survey also notes that there is a great gulf -there are writers living on the poverty level and in the top 10 percent, making $45,000 or more a year, and the top five percent, with incomes of $80,000 or beyond.

Secretary of State Alexander M. Haig Jr. and Foreign Minister Huang Hua of China concluded the first of three days of Chinese-American talks today in apparent agreement on the need for closer strategic cooperation to counter Soviet activities around the world. A senior aide to Mr. Haig, in briefing reporters after the two-hour meeting, said there was ''a great deal of unanimity'' that the main problem in the world today was ''Soviet hegemonism.'' Hegemonism is the shorthand term used by the Chinese to criticize Soviet the expansion of Soviet power. Mr. Huang, in a banquet toast tonight, said that the Chinese ''attach importance to the strategic relationship between China and the United States'' despite the differences that exist between them ''in policy and viewpoint.''

Representative Ed Jenkins, a Democrat from a district of small farms and businesses in north Georgia, says he hopes the Ways and Means Committee ''can stick with across-theboard'' cuts in personal income tax rates. Representative Thomas J. Downey, a Democrat from a district of suburbs and small businesses on the south shore of Long Island, wants to find another way to cut taxes, perhaps by widening existing income brackets. Mr. Downey, Mr. Jenkins and three other Ways and Means Democrats will meet for the first time tomorrow as a task force appointed by the committee chairman, Dan Rostenkowski of Illinois, to advise the Democrats how best to shape this part of a tax-relief bill. Stresses Among Democrats The difference in approach between Mr. Jenkins, a conservative, and Mr. Downey, a liberal, is typical of the stresses that already have sundered House Democrats. Leaders of the conservative wing have pledged to support President Reagan's bill to cut personal tax rates by 25 percent over 33 months, starting with a 5 percent cut Oct.1. There would also be cuts of 10 percent on July 1, 1982, and July 1, 1983.