Formal Notation
The negation of conjunction rule may be written in sequent notation:
The negation of disjunction rule may be written as:
In rule form: negation of conjunction
and negation of disjunction
and expressed as a truth-functional tautology or theorem of propositional logic:
where, and are propositions expressed in some formal system.
Read more about this topic: De Morgan's Laws
Famous quotes containing the word formal:
“Two clergymen disputing whether ordination would be valid without the imposition of both hands, the more formal one said, “Do you think the Holy Dove could fly down with only one wing?””
—Horace Walpole (1717–1797)