Chief of Software Unit at Lotus Quits

A top officer at Lotus Development Corp. has resigned from the computer software company because of management disagreements with the firm’s chairman and other senior executives, the company said Friday.

Charles J. Digate, 34, a senior vice president in charge of the company’s Analytic Software Group, resigned Thursday “under mutual agreement,” a company statement said.

But company sources quoted in several published reports said Digate’s resignation was urged by Lotus Chairman Jim P. Manzi, 36, because his brusque style upset other top executives.