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One Plus One Equals Two (2006)
From the highly eclectic blog of Mark Dominus
Principia Mathematica is an odd book, worth looking into from a historical point of view as well as a mathematical one. The Principia Mathematica will define the sum of cardinal numbers p and q something like this: take a representative set a from p; a has p elements. Post scriptum: Peter Norvig says that the circumflex in the Principia Mathematica notation is the ultimate source of the use of the word lambda to denote an anonymous function in the Lisp and Python programming languages.
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