This discussion follows Kalish and Montague, [1], in part. We distinguish two kinds of meaningful expressions of a formal object language: terms and formulas. Terms and formulas are composed of the following symbols.
Classes of symbols (variables and constants):
Meta-linguistic symbols: For meta-linguistic notation we use Quine's corner notation, e.g. éFù , where the logical constants are used autonymously and Greek characters are metalinguistic variables, with typing as shown in the chart below. We use ':-' for syntactic implication, and ':=' for semantic implication. We use '\' for 'Therefore' when discussing English arguments, and 'À' (with subscripts) to indicate the infinite cardinality of a set.
Abbreviations: We use this notation for the signature of a symbol
<Type(logical constant/non-logical constant/variable), Arity(Number), Usage(prefix/infix/suffix/bracketing), Makes(term/formula), VariablesBound(Number), TermsTaken(Number), FormulasTaken(Number)>
to encode the following information pertaining to syntactic characteristics of logical and non-logical symbols.
Type of symbol:
Arity of symbol
Usage of symbol:
Constants:
Definition
Meta-Language Variables
| Operation variables |
|
| Predicate variables |
|
| Individual variables |
|
Object Language Variables
| Operation variables |
|
| Predicate variables |
|
| Individual variables |
|
Logical Constants and VBOs
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Object language symbols: Non-logical constants and VBOs
Set-theoretic Symbols
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Arithmetical Symbols
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Symbols of Differential and Integral Calculus
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
à Possibility
↵ Necessity
References:
[1] Kalish, D., Montague, R., and Mar, G.
Logic: Techniques of Formal Reasoning (2nd Edition)
Harcourt, Brace & Johanovich, Inc.
New York, 1980