Exponents of Subvarieties of Upper Triangular Matrices over Arbitrary Fields are Integral
Partially supported by grant RFFI 98-01-01020. Let Uc be the variety of associative algebras generated by the algebra of all upper triangular matrices, the field being arbitrary. We prove that the upper exponent of any subvariety V ⊂ Uc coincides with the lower exponent and is an integer.