Tantalizer 495: Bound variables
28 December 2016
Posted by on
From New Scientist #1046, 7th April 1977 [link]
Morning coffee at the Logicians’ Union could be with or without any or all of milk, sugar and biscuits. You ordered as you went in by putting your name on any or all of three lists headed “milk”, “sugar” and “biscuits”.
Well, that was not too hard and, by the time Professor Haarschneider was half way through his seminal paper on Semi-opaque Designators, 21 names appeared under each heading. It fell to Professor Nachtwebel, as president, however, to regroup the names into the appropriate seven subsets. Working on the back of an envelope in Polish notation, he found that no two subsets were the same size, that the smallest had three members and that the largest was of those requiring milk but neither sugar not biscuits.
As it was by now the hour appointed for luncheon, the delegates had to forego coffee. How many of those who would have taken sugar were also hoping for biscuits?