The minimum number of idempotent generators of a complete blocked triangular matrix algebra

Let R be a complete blocked triangular matrix algebra over an infinite fiel d F. Assume that R is not an upper triangular matrix algebra or a full matr ix algebra. We prove that the minimum number v - v(R) such that R can be ge nerated as an F-algebra by v idempotents, is given by [GRAPHICS] where m(1) is the number of 1 x 1 diagonal blocks of R. We also show that R can be generated as an F-algebra by two elements, and if m(1) - 0, R can b e generated by an idempotent and a nilpotent element. (C) 1999 Academic Pre ss