Used in definitions of a term and formula of a and f ¸ ⁿ, P ¸ ⁿ, A, B, x (and further it is possible x ₁, x ₂ etc.) — the meta language signs called by also variables which possible are expressions of the corresponding of the described (object) language.
Developed in modern symbolical logic creation of logical calculations is its major result. Its theoretical and practical consists that thanks to it there is a of the proof of any formula representing logicians from an infinite set of such formulas, and also to carry out the corresponding conclusion for any — besides from an infinite set of cases from
We axiomatic system of calculation of predicates, having added to the listed above schemes of calculation of statements (meaning, of course, transition to language of logic of a predicate the following four and one rule:
Pay attention when the statement precedes a community quantifier (that is the initial statement is the general), the logical connective ⊃ is used further; in a when that is the existence quantifier (the is private), for its record on YaLP the sheaf &.
In conclusion of this section concerning semantics of language it is important to notice that though rules of attributing of the to expressions of language making in total this semantics are focused on attributing of values in concrete cases, their major importance consists that they specify the general principles, the general ways of transformation of formulas of language into intelligent expressions. At such interpretation of the specified rules semantics itself the theory of an oznachivaniye of expressions of this language (which call also the theory of a ).