george: User Manual

[ Introduction ] [ File Structure ] [ #check PROP ] [ #check PRED ] [ #check TP ]
[ #check ND ] [ #check ST ] [ Arithmetic ] [ Sets ] [ #check Z ] [ #check PC ]
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Propositional Logic Formulas (#check PROP)

Here is an example of the response to a question that requires a propositional logic formula:

#q 05a

Formalize the following sentence:

If it is windy and cold then I won't go outside.

#check PROP

(a & b) => !c

/*
where
a means it's windy
b means it's cold
c means I go outside
*/

george's syntax for propositional logic formulas follows the rules presented in SE212 (e.g., infix, brackets, precedence, and associativity) with the following ASCII symbols for the operators:

Syntax in george Meaning

! operator not

& operator and

| operator or

=> operator implies

<=> operator iff

false false

true true

Syntax in george	Meaning
!	operator not
&	operator and
\|	operator or
=>	operator implies
<=>	operator iff
false	false
true	true

george's keywords may not be used as identifiers.

What does george check?

For propositional formula, george checks the first non-comment line after the directive to make sure:

The formula is syntactically correct for propositional logic.

The comments are necessary to inform the TAs of the meanings that you associate with each proposition. george expect only one line of propositional logic formula. It does not check a formula split over multiple lines or multiple formulas.