In logic metavariable (also metalinguistic variable[1]) is a symbol or set of symbols in a metalanguage which stands for a symbol or set of symbols in some object language. For instance, in the sentence:
- Let A and B be two arbitrary formulas of a formal language ℒ.
The symbols A and B are not symbols of the object language ℒ, they are metasyntactic variables in the metalanguage (in this case, English) which is talking about the object language ℒ.
Etymology
edit- 'Meta' means providing information about, or transcending.
- 'Variable' means something that can assume a value, or something likely to vary.
So we have a word that
- transcends the common rules of a variable and can assume a value
See also
editReferences
edit- ^ Geoffrey Hunter, Metalogic: An Introduction to the Metatheory of Standard First-Order Logic p.13
External links
edit- Definition of metasyntactic variable, with examples.
- Examples of metasyntactic variables used in Commonwealth Hackish, such as wombat.
- Variable "foo" and Other Programming Oddities