The principal types of elliptical sentences and their usage

A sentence is a proposition expressed by words (something true). A proposition is the semantic invariant of all the members of modal and communicative paradigms of sentences and their transforms. But besides sentences which contain propositions there are interrogative and negative sentences. Speech is emotional. There is no one to one relationship. Then a sentence can be grammatically correct, but from the point of view of logic it won’t be correct, true to life (Water is a gas). Laws of thinking are universal but there are many languages. Grammar and Logic don’t coincide. A sentence is a subject-predicate structure. What are the subject and the predicate? Grammatical subject can only be defined in terms of the sentence. Moreover the grammatical subject often does not indicate what we are `talking about’ (The birds have eaten all the fruit. It is getting cold). Besides, this definition leaves out verbless sentences. There are one-member sentences. They are non-sentences? Conclusion – a sentence is a structural scheme.