Formal expression of the Russian verb aspect and tense

The paper deals with the peculiarities of the formal expression of the Russian verb aspect and tense categories. The author takes into account the traditions of coping with this problem, namely the works of Y. C. Maslov. The perfective and imperfective meaningful verb structures are enumerated, paying attention to the derivational models for the formation of imperfectives, perfectives, general verb forms, and gives the factors determining a verb type. Also, the conditions for the lexeme fixedness are stated. The author describes the formal representation of the verb tense category from the position of the abstract morphological forms and word forms. A new approach is used according to which asymmetry is a characteristic feature in the morphological forms and word forms.