July 8, 1982

The Justice Department's antitrust division today asked the nation's largest telephone companies to provide information on the agreement they reached to provide a new type of mobile phone service in 30 of the nation's largest cities. The antitrust division served information requests on the American Telephone and Telegraph Company, the General Telephone and Electronics Corporation, United Telephone System Inc., the Continental Telephone Corporation and several other companies as part of what it described as a preliminary inquiry. Tom Stewart, a spokesman for the Justice Department, confirmed that a preliminary inquiry had been started. But he declined to confirm or deny that the companies had actually been served with civil investigative demands, as the preliminary requests for information are known.

HATTIE CARTHAN adopts things. When she lived on Long Island as a young girl and drove to and from Brooklyn church services with her father, a minister, she used to ''adopt trees along the road because they came to be familiar to me,'' she says. ''They were my trees.'' She never lost her fondness for trees, and 13 years ago, when she found a rare magnolia tree abloom in front of one of four decaying brownstones on Lafayette Avenue a few blocks from her home in the Bedford-Stuyvesant section of Brooklyn, she adopted that, too. The fact that the tree was very much a botanical freak, reckoned to be almost 100 years old and a species rarely able to tolerate climate conditions north of Baltimore, made it all the more dear to Mrs. Carthan, somewhat akin to an orphan in need of special care.

At lunchtime these days, on the great stone steps of the New York Public Library at 41st Street, they are celebrating the joy of summer. Lunchers lunch, hawkers hawk, gawkers gawk, fiddlers fiddle, preachers preach and thousands of passers-by stop, stare, smile and then move on. That much is not new. What is new is the rejoicing inside the Beaux-Arts building, where library officials are celebrating the end of the first really good year in a long, long time.

Several months ago Dartmouth College called the architectural firm Moore Grover Harper in Essex, Conn., asking for design revisions in an art gallery still in the planning stage. Normally an architect and one or more draftsmen would spend about three days modifying the design, changing the specifications and redrawing the building. This time an architect made the changes on a video screen in a matter of hours and new drawings were in the mail the same day. Such a quick turnaround, which was impossible last year at this firm of 21 employees, is routine now with the help of a computeraided design system (CAD), the latest advance in the computer revolution. ''In the old days an architect did most drawings on scratch paper and then gave them to an employee who made the formal pencil drawings with triangles, compasses and all that,'' said William H. Grover, a partner in the firm.

President Reagan's offer of American troops to help guarantee the evacuation of Palestine Liberation Organization forces from west Beirut seems to mark a new turn in what has amounted to an awkward diplomatic minuet between the United States and the Palestinian organization for the last seven years. During this period, the United States has followed a policy of refusing to deal with the P.L.O. until it met certain Israeli conditions. In the indirect negotiations that Philip C. Habib, the special American envoy, has conducted in Beirut with the Palestinians, there is still no sign that the policy is about to change. But some officials said that once the Lebanese crisis was over, and if the Palestinian leadership emerged intact, more productive discussions might develop. Administration officials said today that the move to extricate the Palestinians from possible annihilation by Israel came after their leaders had urged the United States repeatedly to drop its ban on direct diplomatic contacts.