De Morgan's law

Meaning

Noun

• Either of two laws in formal logic which state that:
• Either of two laws in set theory which state that:
• Any of various laws similar to De Morgan’s laws for set theory and logic; for example: ¬∀𝑥 𝑃(𝑥) ⇔ ∃𝑥 ¬𝑃(𝑥)

Origin

• Named after the British mathematician and logician Augustus De Morgan (1806–1871), who first formulated the laws in formal propositional logic.