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2.2.1 Logical Constants

The following logical constants are formulas:

Syntactic Forms  Logical constants may appear in various forms, e.g. as

The last form is most frequently used; please do not confuse these formulas with the truth values true and false.

Definition 4 (Semantics of Logical Constants) The meaning of `F' is false and the meaning of `T' is true

Again, please note the distinction between the two layers of syntax (`F', `T') and semantics (true, false).

The Logic Evaluator uses the syntax false and true both for (the input of) logical constants and for (the output of) truth values. However, by above explanation it should be clear that the input denotes a formula while the output prefixed by the token `>' denotes the meaning of this formula.

Author: Wolfgang Schreiner
Last Modification: October 4, 1999

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