Lyford Greene, 91, a former chief economist of AT&T who...

Lyford Greene, 91, a former chief economist of AT&T who helped influence federal regulation of the telephone system, died Tuesday of complications from heart disease at White Plains (N.Y.) Hospital. He was chief economist at AT&T when the federal government was increasing its regulation of public utilities and their pricing policies. He was a strong proponent of the notion that capital-intensive industries, like the telephone system, need to earn a sufficient rate of return on their investments in plant and equipment. In that role he was closely involved in AT&T's responses to the rate cases that the federal government brought to regulate telephone rates.