Augustus De MorganBorn 27 Jun 1806; died 18 Mar 1871 at age 64. English mathematician and logician who did important work in abstract symbolic logic, the theory of relations, and formulated De Morgan's laws: one is “NOT (A AND B) = (NOT A) or (NOT B)” and the other is “NOT (A OR B) = (NOT A) AND (NOT B)”. These laws continue to be applied in modern proof theory and for software programming. When he defined and introduced the term “mathematical induction” (1838), he gave the process a rigorous basis and clarity that it had previously lacked. He originated the use of the slash to represent fractions, as in 1/5 or 3/7. In Trigonometry and Double Algebra (1849) he gave a geometric interpretation of complex numbers.«[Born in India, De Morgan (according to Macfarlane) De Morgan considered himself to be British, without being specifically English, Scottish, Welsh or Irish.] |
