But his analysis differs in several essential points from the Classical schema: there is no question of the potential, underlying, invisible addition of the attributive function, and of the propositional meaning attributed to the verb to be; it is a question primarily of a material junction between a radical and the forms of the verb to be: the Sanskrit as is to be found in the sigma of the Greek aorist, in the er of the Latin pluperfect and future perfect; the Sanskrit bhu is to be found in the of the Latin future and imperfect.