in reply to Pairing Riddle (OT)

Given the down votes it attracted, it might have been better to motivate it with breeding dogs to avoid touching on taboos.° =)

But I enjoyed it from a mathematical perspective, since it's a a problem which can be perfectly described in graph theoretic terms: a directed graph with a "child of" relation with certain restrictions:

Here the solution in short, but hidden behind a spoiler tag to protect those interested.

Cheers Rolf
(addicted to the Perl Programming Language :)
see Wikisyntax for the Monastery

°) apparently do most so called "purebred" dogs have an inbreeding factor of 25%. That's like the outcome of incest. One more reason why I'd always opt for a mongrel.

¹) in some western countries this is technically legal, because the laws don't cover that case.

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Re^2: Pairing Riddle (OT)
by Ratazong (Monsignor) on Apr 27, 2026 at 07:49 UTC
    Hi LanX, there is another possibility not mentioned in your spoiler: seems to be much easier than originally thought ... but does not involve any graph-theory ...

    So long, Rata

      Thanks, Rata. But I think you missed the requirement in the OP that uncle/aunt by marriage doesn't count.

      > > > "Direct" means blood related, i.e sibling of one parent, not "uncle by marriage".

      In hindsight it becomes clearer why breeding dogs would be a better setting for this puzzle.

      Dogs don't know marriage, divorce and soap operas° ... ;)

      And many breeders rely on incest, restricting them to uncle/aunt relationships would be a "moral" advantage.

      Update

      The trivial solution (of many) if "by marriage" was allowed ...

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      see Wikisyntax for the Monastery

      °)