How to Write Well-formed Formulas:

• Propositional Variables: Use elements in Prop.
• Negation: Use the tilde symbol ~ before the propositional variable or formula. E.g., ~p.
• Conjunction: Use the ampersand symbol & between two formulas. E.g., (p&q).
• Disjunction: Use the plus symbol + between two formulas. E.g., (p+q).
• Brackets: Every formula connected by a binary operator should be enclosed within a pair of brackets. E.g., (p&q), not p&q.