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Parity Dance (Posted on 2024-06-19) Difficulty: 3 of 5
Find all non-empty finite sets of integers A and B with the following properties:

(i) Whenever x∈A, x+1∈B.
(ii) Whenever x∈B, x2-4∈A.

No Solution Yet Submitted by Danish Ahmed Khan    
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Solution Semi-analytical solution (spolier) | Comment 2 of 3 |
Combining the two properties, we conclude that
     whenever x∈B, (x2-3)∈B.

I tried the integers from -5 to 5, and the only finite set B that seemed to work was B = {-2, 1}.  Which makes the only A = {-3,0}


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Except I seem to be wrong.  I just saw Larry's solution, which I like better

Edited on June 19, 2024, 10:29 am
  Posted by Steve Herman on 2024-06-19 10:24:31

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