In the early 1990s, Solipsys Limited was founded to cover a range of various activities. Over time these have evolved primarily into a selection of talks and workshops covering a range of mathematical ideas.
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Some time ago I gave a talk in which I showed that something unexpected happened with a deck of playing cards. I had some volunteers try it, and while they did so I talked about just how many orderings there are for 52 cards. I computed (an approximation to) $52!$ (52 factorial) by hand. It's not so hard - you just…
One of my favourite Limited Audience Jokes (although technically it's actually a riddle) goes:
One of my favourite Limited Audience Jokes (although technically it's actually a riddle) goes:
Recently I've been discussing the details of measuring the size of the Earth by watching a shadow descending a wall at sunrise, or ascending at sunset. The sums are easy enough if you do it at either Equinox, and at the Equator, and you can read about it here: