Logic 101 (#19): DeMorgan’s Law, Part 1
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Fun fact: p ^ q is the same thing as ~(~p v ~q).
The rule is named after Augustus De Morgan, a 19th Century British mathematician. Some refer to it as a “rule,” others a “law,” and yet others a “theorem.” It’s the same thing in each case.
http://en.wikipedia.org/wiki/Augustus_De_Morgan