Tantalizer 434: Limited editions
6 March 2019
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From New Scientist #985, 29th January 1976 [link]
Boremaster’s commentary on Hegel being a basic book, our library has several copies. It is not exactly a jolly read, as you will know if you have ever waded through its 36 chapters, but is much in demand on the ground that it is less painful than Hegel himself. Even so I was surprised to meet my friend Jones leaving the library with three copies under his arm.
“Steady on, old bean!” I exclaimed, “there are other readers to think of.”
“The other copies are all on the shelf”, he replied airily, “but I had to take three to get a complete text. Some rotter has snipped whole chapters out of every copy.”
“Well, surely two copies would have done?”
“No. No two copies would yield a full text.”
“Do you mean that I shall have to check every copy, if I want to be sure of a full text?”
“Oh no. Just take any three at random, as I did. You are bound to get a full text, even through no chapter is present in all copies. For each pair of chapters there is at least one copy with only one of them.”
For this to be true, how few copies need the library have in total?