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Augustus De Morgan (1806 - 1871)

Augustus De Morgan (1806-1871)Augustus De Morgan was a brilliant mathematician and professor noted for his advances in algebra and logic. He was a friend of Charles Babbage (inventor of the Analytical Engine, forerunner of the modern computer) and he tutored Ada Lovelace, who was the poet Lord Byron's daughter and supposedly wrote the first computer program for Babbage's machine. De Morgan was prolific and wrote such mathematical texts as Elements of Arithmetic (1830), Penny Cyclopedia (1838) where he coined the term 'mathematical induction', Trigonometry and Double Algebra (1849), a geometric interpretation of complex numbers, and Formal Logic (1847), one of his most important works.

De Morgan was an uncompromising advocate of religious liberty and free expression; while at Trinity College he would not sign required theological forms and was therefore not allowed to continue with his graduate eduation and fellowship. He was a founder, with George Boole, of symbolic logic as it developed in England. He wrote many books and articles, including Trigonometry and Double Algebra and Formal Logic. He is perhaps best known as the creator of De Morgan's Laws:

NOT (A AND B) = (NOT A) OR (NOT B)
NOT (A OR B) = (NOT A) AND (NOT B)

These statements show that negating an AND makes it an OR and vice-versa. These laws have become some of the most frequently applied in modern proof theory and are widely used in software programming as well.

Less known was DeMorgan's love and collection of paradoxes, puzzles, riddles, lore, odd opinions of the learned, and anecdotes. To sample this part of his contribution, select one of the following excerpts from his book A Budget of Paradoxes (1872):

The astronomer's drinking song
On curiosities of Pi
Buffon's needle problem

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