Definition:Metalanguage/Metasymbol
Definition
A metasymbol is a symbol used in a metalanguage to represent an arbitrary collation in the object language.
Metasymbols are deliberately taken from a set of symbols that are not in the alphabet of the object language in question.
On $\mathsf{Pr} \infty \mathsf{fWiki}$, metasymbols are usually taken from any of:
- uppercase letters: $P, Q, R, \ldots$ and subscripted versions: $P_1, P_2, \ldots$
- the Greek alphabet: $\phi, \chi, \psi, \ldots$ and their subscripted versions: $\phi_1, \phi_2, \ldots$
- uppercase bold: $\mathbf A, \mathbf B, \mathbf C, \ldots$ and their subscripted versions: $\mathbf A_1, \mathbf A_2, \ldots$
Which system is in use on a particular page depends to a certain extent on the nature of the source work which has inspired it.
Examples
Quotation Marks
It is commonplace to use quotation marks to indicate that the enclosed expression is under consideration independently of what the expression actually stands for.
Hence it is a metasymbol.
Also known as
A metasymbol can also be referred to as:
Some sources also use the term propositional variable, but this has subtly different meaning on $\mathsf{Pr} \infty \mathsf{fWiki}$.
Also see
- Results about metasymbols can be found here.
Sources
- 1959: A.H. Basson and D.J. O'Connor: Introduction to Symbolic Logic (3rd ed.) ... (previous) ... (next): $\S 4.2$: The Construction of an Axiom System
- 1965: E.J. Lemmon: Beginning Logic ... (previous) ... (next): Chapter $2$: The Propositional Calculus $2$: $1$ Formation Rules