[2.4] Exercise 8
For a given set \(N\), there can be at most one set \(M\) such that \(N,M\) is an Euler pair. Why? Think backward: "If there were two different such sets, \(M\) and \(M'\), then there would have to be some smallest integer.

Example 1

$$ \begin{align} 6 &= 1 + 1 + 1 + 1 + 1 + 1 \\ 6 &= 2 + 2 + 1 + 1 \\ 6 &= 2 + 1 + 1 + 1 + 1 \\ 6 &= 4 + 1 + 1 \\ 6 &= 4 + 2 \\ 6 &= 3 + 1 + 1 + 1 \\ 6 &= 3 + 2 + 1 \\ 6 &= 3 + 3 \\ 6 &= 2 + 2 + 2 \\ 6 &= 5 + 1 \\ 6 &= 6 \end{align} $$

References