sci-hub.tw [PDF] · #math

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__Login__or__Take a Tour__!I got to wondering where all those toy problems used in graph search examples came from.

One was proposed for the SexAT:

**17. De tribus fratribus singulas habentibus sorores**

**Three friends and their sisters**

Three friends each with a sister needed to cross a river. Each one of them coveted the sister of another. At the river they found only a small boat, in which only two of them could cross at a time. How did they cross the river without any of the women being defiled by the men?