Principia Mathematica
Let's look at some messages from Principia Mathematica .... signaling events that occurred between year 1910 and now, year 2014.
en.wikipedia.org/wiki/Principia_Mathematica
Wikipedia
PM, as it is often abbreviated, was an attempt to describe a set of
axioms and
inference rules in
symbolic logic from which all mathematical truths could in principle be proven.
The messages are via BLOG posts that are sub-page TITLES listed on the left of your computer screen. Select on a title.