Key points are not available for this paper at this time.
The article proposes a cognitive revision of sentence invariants with respect to the explication of main parts. Confusing `composition' and `structure' and bringing a morphological nomenclature of word classes to nominate invariants is a methodological problem. Extrapolation of terms from level to level adds contradiction to the categories and is a problem in the learning and acquisition of the language and its grammar. A cognitively correct sentence on this basis is one-component, subject or predicate, subject or predicate, but not one-component, because they are parts of the structure, not of the composition. The predicate sentence is always personal, but when it is expressed by a verb with a form in the third person only, i.e. in principle, there is no first and second position of the paradigm of this morphological category, it is subjectless.
Mariana Georgievа (Fri,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: